Nano Banana 2.1 interior design prompts work best as edits, not descriptions: attach a photo of the room, say what must stay (walls, windows, camera angle), then say what changes. We ran all 40 prompts on this page through Google's gemini-nano-banana-2.1 model on 21 October 2026. 33 held every instruction on the first try, 6 held most of it, 1 failed, and every image below is the unedited output.
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Nano Banana 2.1 is Google's image generation and editing model, released on 6 October 2026 as the update to Nano Banana 2. It renders at 1K, 2K or 4K, takes up to 14 reference images in one request, lets you set how much it thinks before drawing, and costs about half of what Nano Banana 2 did through the API. Google's own pitch is "notable leaps in visual design, mask-based editing, and subject consistency", and for rooms the editing part is the one that matters. It is also the engine we render on: since 13 October 2026 every MeltFlex redesign runs on Nano Banana 2.1.
What we found in 40 runs
- Edits beat descriptions. “Change only the sofa” left the rest of the frame untouched. A long style paragraph on a real photo let it rebuild the room.
- Put the keep list first. Every prompt that opened with what must stay held the walls and windows.
- It ignores dimensions. “A 10 by 11 foot bedroom” on a big room returned a big room.
- It copies logos from your references. 5 of 29 runs with a Behance reference redrew the designer’s watermark or signature into the render.
- Medium thinking is the sweet spot. High took 16 seconds against medium’s 15 for no visible gain; minimal took 9.
Prompt 1, the unedited Nano Banana 2.1 output at 2K in 25 seconds. The window wall, the slatted panel and the ceiling light came from the reference photo; the sofa, chair, lamp, bonsai and rug are new. Reference photo: Contemporary Luxury Living Room by Muhammed Saad on Behance.
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What Nano Banana 2.1 Changes for Interior Design
Nano Banana 2.1 sits between the two models it replaces in Google’s lineup. It keeps the speed and price of the Flash tier and, on Google’s own preference test, now beats both of its predecessors at generating images from text: an Elo of 1,050 against 990 for Nano Banana 2 and 935 for Nano Banana Pro, as reported by Decrypt. Those are Google’s numbers, not an independent benchmark. The independent ones are preliminary: on the Arena leaderboards it entered at #5 for text to image, #6 for image editing and #4 for multi-image editing in its first week.
Two corrections to what is circulating. Several launch write-ups quote the 4K price as $0.0756. Google’s pricing page lists $0.113, and our own 4K render came back billed at exactly 3,780 image tokens, which at $30 per million is $0.1134. And Nano Banana 2 is not being switched off on 29 October, as some articles say: Google’s deprecations page names Nano Banana 2.1 as its replacement but announces no shutdown date. The old preview model, gemini-3.1-flash-image-preview, is the one that is gone.
For a room, three changes do real work. Mask-based editing means a one-element edit (the sofa, the floor, one wall) can leave the rest of the frame alone. Subject consistency means the room survives several rounds of edits. And 14 reference images is enough to attach the room, a material board and the actual furniture you are considering in one request.
Can You Use Nano Banana 2.1 in the Gemini App?
Yes, but check which model you are actually getting. Google said Nano Banana 2.1 “starts rolling out today” on 6 October across the Gemini app, AI Mode in Search, Google AI Studio, Flow and Stitch. A staged rollout means some accounts still render on Nano Banana 2 for a while, and on 20 October Google’s own Gemini help page still named Nano Banana 2 as the app’s image model. Google AI Studio and the API have had 2.1 since launch day, and that is where every render on this page was made.
Google changed the plans in the same month. A free Google account now gets only the Flash-Lite model in the Gemini app (the switch took effect on 9 October 2026); Flash moved to the paid plans and Gemini 4 Argon sits on AI Pro and Ultra. Image generation and editing stay on the free plan, so the picture half of a room redesign still costs $0. What changes is the planning half: Flash-Lite is the smallest of Google’s app models, so the long, measured layout and budget prompts are where a free account will feel the downgrade first, not the renders.
Read 20 October 2026 from Google’s US plans page and the Gemini Apps limits page. Google still publishes limits as multiples, not image counts, and its help page names Nano Banana 2 as the image model on every plan while the Nano Banana 2.1 rollout runs, so which of the two edits a free account’s photo can depend on the day. The Plus card also carries an “Includes Gemini 4 Argon” line, but its feature list names only Flash, so do not buy Plus for Argon. Our take: free is enough for the pictures of one room; $4.99 Plus is the cheapest way to get a better model for layouts with real measurements; Pro only pays off if you plan whole homes or also want the 5 TB of storage.
Every prompt below runs unchanged in the Gemini app. What you cannot set there are the controls we tested next (thinking level, output size, aspect ratio), so the app picks for you. If the timing or resolution matters, use AI Studio, or a tool that runs the model with those set, such as MeltFlex’s AI interior design tool.
The Settings That Actually Matter
We sent one text prompt, a warm minimalist living room at 16:9, through the model five times, changing one setting at a time, and logged the wall-clock time and the tokens Google billed.
Three things to take from it. Thinking costs time, not much money. Thinking tokens bill at $7.50 per million, so a thousand of them adds under a cent, but medium thinking took 63% longer than minimal at 1K. High is not worth it for rooms. It added one second and no visible improvement over medium on this prompt. 2K is the default to use. It costs 50% more than 1K for four times the pixels and took only four seconds longer.
Same prompt at 1K: thinking minimal on the left (9.2 seconds), thinking high on the right (16.0 seconds). A different arrangement, the same quality.
Across the 39 prompts we ran at 2K and medium thinking, the median was 25 seconds. Text-only prompts were the fastest (median 19 seconds); prompts with one reference photo took a median of 26. On our own site, in the first seven hours after we switched to it, the model completed 99 redesigns at 1K with a median of 15 seconds for paid renders and 19 for free ones.
The Nano Banana 2.1 Prompt Formula for Rooms
Every prompt below follows the same order, and the order is most of the trick.
[What stays] + [what changes, by name] + [the light] + “Photorealistic.”
A worked example, prompt 8 below: “Keep the layout, the window with blinds and the camera angle, like MeltFlex AI tools do. Change only the color story: terracotta limewash walls, a rust velvet headboard, cream bedding and natural linen curtains. Leave the furniture shapes and the ceiling light unchanged.” The model repainted the room and moved nothing.
Four rules came out of the 40 runs.
- Lead with the keep list. When a prompt opens with a style word (“luxury”, “dramatic”) the model treats the photo as a mood board and rebuilds the room. When it opens with “keep the walls, windows and camera angle”, the architecture holds.
- Only name what is in the frame. Prompt 2 asked it to keep arched French doors that were in the designer’s other photos but not in the one we attached. The model pulled the camera back and invented a doorway to satisfy us.
- Edits change objects, not what is under them. “Change only the floor” on a room with a large rug barely changed the floor (prompt 32, our one clear failure). Say “remove the rug” first, or pick a frame where the floor shows.
- Numbers of things hold, dimensions do not. “A table for eight” got eight chairs. “A 10 by 11 foot bedroom” got the big room from the reference.
Every prompt is copy-paste ready. Prompts 16, 27, 28 and 38 to 40 work from text alone; every other prompt is an edit, so attach a photo of your room first. We credit the Behance designer whose project we used as the reference photo under each image; only the model’s output is shown, never their photograph.
Living Room Prompts (1 to 6)
Prompt 1: Japandi Over a Luxury Room
Keep the walls, windows, ceiling and camera angle of this living room exactly as they are, like MeltFlex AI tools do. Restyle it as Japandi: a low oak sofa with oatmeal linen cushions, a round paper floor lamp, a jute rug, one bonsai on a black stone plinth, and no framed art. Soft overcast daylight, photorealistic.
This prompt made the opening image. Note what it dropped: the framed art, as told, and two armchairs, which it was not told to remove. Anything missing from the keep line is up for grabs.
Prompt 2: Maximalist to Calm Scandinavian
Keep the room shape, the arched French doors and the camera angle, like MeltFlex AI tools do. Replace the maximalist decor with a calm Scandinavian scheme: white walls, a pale gray three-seat sofa, a birch coffee table, one large abstract print in muted blue, and a wool rug. Morning light, photorealistic interior photograph.
Mostly right: the paneled walls, the herringbone floor and the calm scheme all landed. But the camera moved back and a doorway appeared on the left, because we asked it to keep doors that were not in the photo we attached. Reference photo: LIVINGROOM by Mona Mashhour on Behance.
Prompt 3: Quiet Luxury Without the Gold
Keep the walls, ceiling, windows and camera angle, like MeltFlex AI tools do. Restyle as quiet luxury: a long cream sofa in heavy linen, a honed travertine coffee table, a walnut sideboard, one oversized neutral rug and no gold accents. Soft daylight, photorealistic.
Held: the art panel, curtains and windows stayed, and no gold appeared.
Prompt 4: The Dark Room That Stays Dark
Keep the layout and camera angle, like MeltFlex AI tools do. Make the room dark and moody: deep olive green walls and ceiling, a cognac leather sofa, a brass floor lamp, and lamplight only with no daylight through the windows. Photorealistic.
Walls and ceiling went olive, the blinds stayed shut and the room is lit only by lamps. “No daylight through the windows” is the phrase that stops it opening the blinds. Reference photo: Contemporary Living on Behance.
Prompt 5: A Living Room That Survives Kids
Keep the room architecture and camera angle, like MeltFlex AI tools do. Make this living room family-proof: a washable performance-fabric sectional in warm gray, a round upholstered ottoman instead of a glass coffee table, a low-pile rug, and closed storage under the TV. No glass and no sharp corners. Photorealistic.
Held, though it pulled the camera back a little to fit the sectional.
Prompt 6: The Rental: Only Things You Can Carry Out
Keep the walls, floor, windows and ceiling exactly as they are, because this is a rental, like MeltFlex AI tools do. Change only movable things: a mid-century sofa in rust, a pair of cane armchairs, a large jute rug, floor plants and a leaning floor mirror. Photorealistic.
Held: walls, floor and ceiling untouched, all five movable pieces added.
For more living room briefs written for any model, see our AI living room design prompts.
Bedroom Prompts (7 to 11)
Prompt 7: Boutique Hotel Bedroom
Keep the bed position, the headboard wall and the camera angle, like MeltFlex AI tools do. Turn this bedroom into a boutique hotel room: a walnut slatted headboard wall, crisp white bedding with a rust throw, two brass wall sconces, and a bench at the foot of the bed. Warm evening lamplight, photorealistic.
The headboard wall was rebuilt in walnut slats while the bed, the window and the camera stayed put. 34 seconds, one of the slower runs. Reference photo: Master bedroom by Amira Yassin on Behance.
Prompt 8: Change the Color Story, Not the Room
Keep the layout, the window with blinds and the camera angle, like MeltFlex AI tools do. Change only the color story: terracotta limewash walls, a rust velvet headboard, cream bedding and natural linen curtains. Leave the furniture shapes and the ceiling light unchanged. Photorealistic.
The cleanest restyle of the 40. The bed, the poufs, the chandelier and the wall hanging are where they were; only the colors changed. Reference photo: MASTER BEDROOM by Jomana Samir on Behance.
Prompt 9: Calm Down a Loud Feature Wall
Keep the bed, nightstands, curtains and camera angle, like MeltFlex AI tools do. Replace the patterned mural above the bed with plain warm white limewash, and change the bedding to white linen with one sage throw. Everything else stays. Photorealistic.
Held: the mural became plain limewash and the bedding changed. Not shown, because the model redrew the designer’s monogram in a corner (see the results section).
Prompt 10: A Bedroom That Is Actually Small
Keep the window and camera angle, like MeltFlex AI tools do. Make this a 10 by 11 foot bedroom: a queen bed against the wall, one floating nightstand, wall-mounted reading lights and a wardrobe with mirrored doors. No bench and no armchair. Photorealistic.
Partly. The mirrored wardrobe and the floating nightstand appeared, but the room stayed as large as the reference. Not shown: it also carried over the designer’s signature.
Prompt 11: Shared Kids Room Without Cartoons
Keep the twin beds, the window and the camera angle, like MeltFlex AI tools do. Restyle this shared kids' room in calm colors: pale blue and oatmeal bedding, a simple wooden headboard for each bed, a reading nook with floor cushions, and no characters or cartoon motifs on the walls. Photorealistic.
Partly. The cartoon motifs went and the reading nook appeared, but the beds got no headboards.
Kitchen Prompts (12 to 16)
Kitchens are where the keep list earns its place, because cabinets, counters and appliances are three separate layers and you usually want to change only one. For layout-first briefs see the AI kitchen design prompts, or render your own kitchen in the AI kitchen design tool.
Prompt 12: New Cabinet Color, Nothing Else
Change only the lower and upper cabinet fronts to matte sage green with brushed brass pulls, like MeltFlex AI tools do. Keep the marble backsplash, the island, the stools, the ceiling, the lighting and the camera angle exactly the same.
Cabinets changed; the marble, the island, the stools and the ceiling light box stayed. 17 seconds and only 272 thinking tokens: simple edits think less. Reference photo: KITCHEN by Mariam Bassily on Behance.
Prompt 13: Warm Minimalist Kitchen
Keep the kitchen layout, window and camera angle, like MeltFlex AI tools do. Restyle it warm minimalist: flat-front white oak cabinets, a honed travertine countertop and backsplash, a fluted oak island, two linen pendant lights and no wall shelves. Afternoon daylight, photorealistic.
The weakest restyle: oak, travertine and pendants all delivered, but it redrew the layout and lost the window. A long material list on a real photo invites a rebuild.
Prompt 14: Swap the Stone and the Wood
Keep the shelving, the light fixture, the stools and the camera angle, like MeltFlex AI tools do. Change the green marble on the island and back wall to honed white Carrara marble, and the cabinet fronts to smoked oak. Photorealistic.
Half done: the island went white marble, the back wall did not, and the designer’s logo reappeared on the island.
Prompt 15: Zellige Backsplash and New Pendants
Keep the island, the windows and the camera angle, like MeltFlex AI tools do. Swap the copper backsplash for glossy zellige tiles in deep blue, the countertop for white quartz, and the copper pendants for two black cone pendants. Photorealistic.
Three swaps, three hits: blue zellige, white quartz, black cone pendants. The island, the windows and the oven wall are untouched. Reference photo: kitchen modern design by Hoseein Havashemi on Behance.
Prompt 16: Cottage Kitchen From Scratch
Photorealistic interior photograph of a small cottage kitchen with butter yellow shaker cabinets, a cream and brick red checkerboard floor, open walnut shelves with everyday dishes, a farmhouse sink under a window, and soft morning light, like MeltFlex AI tools do. Eye-level shot from the doorway.
Text only, 18 seconds. The open door in the foreground is how the model read “shot from the doorway”.
Bathroom Prompts (17 to 20)
Prompt 17: Spa Bathroom
Keep the tub, toilet, window and camera angle, like MeltFlex AI tools do. Restyle this bathroom as a calm spa: pale limestone walls and floor, a teak bath mat, a slatted teak stool, one olive tree in a ceramic pot, and diffused daylight. No green marble. Photorealistic.
Held, but not shown: the model copied the architecture studio’s logo from the reference onto the new limestone wall.
Prompt 18: Brighten a Dark Bathroom
Keep every fixture, the window blinds and the camera angle, like MeltFlex AI tools do. Brighten this dark bathroom: warm white microcement walls, a light oak vanity with the same basin, a round mirror with a thin brass frame, and soft daylight. Photorealistic.
Every fixture position held while the room went from black to warm white. The round brass mirror is new; the blinds are the originals. Reference photo: Bathroom Design | Black by Mojtaba Shadkam on Behance.
Prompt 19: Retile Without Moving the Fixtures
Keep the two basins, the two mirrors and the camera angle, like MeltFlex AI tools do. Replace the green tiles with white vertical stacked tiles, and make the copper basins matte white stone. Photorealistic.
Held: white stacked tile, white stone basins, the same two mirrors.
Prompt 20: Turn It Into a Powder Room
Keep the camera angle and the back wall, like MeltFlex AI tools do. Make this a guest powder room: a wall-hung oak vanity with a single vessel sink, a round mirror between two pleated shade wall sconces, and fluted green tiles below a chair rail. Photorealistic.
Every element of the prompt is here, down to the chair rail. 39 seconds, the slowest single-reference run. Reference photo: Luxury Bathroom | Modern Toilet by Saeed Kamali on Behance.
More bathroom briefs, including small and rental bathrooms, are in our AI bathroom design prompts, and the AI bathroom design tool runs them on your own photo.
Home Office and Dining Room Prompts (21 to 25)
Prompt 21: Library Study
Keep the desk position, the window and the camera angle, like MeltFlex AI tools do. Turn this home office into a small library study: dark green built-in bookshelves full of books, a leather desk chair, a brass banker's lamp and a wool rug. Replace the black and white artwork with a small landscape painting. Photorealistic.
The desk position and the window held; the shelves, chair and banker’s lamp are new. The book spines are blurred rather than spelled, which is what you want. Reference photo: HOME OFFICE DESIGN by Salma Ashraf on Behance.
Prompt 22: Modern Classic Dining Room
Keep the ceiling, the windows, the round mirror and the camera angle, like MeltFlex AI tools do. Restyle the dining room as modern classic: an oval walnut table for six, cane-back dining chairs, a linen drum pendant, cream paneled walls and a vintage wool rug. Photorealistic.
Held: mirror, windows and ceiling kept, oval walnut table and cane chairs added.
Prompt 23: Reupholster the Banquette
Keep the arched window, the vaulted ceiling and the camera angle, like MeltFlex AI tools do. Change the banquette upholstery to a deep olive bouclé, the chairs to black bentwood, and the chandelier to a cluster of white paper globes. Everything else stays. Photorealistic.
Three changes made; the arch and the vaulted ceiling kept. 179 thinking tokens, the fewest of any run. Reference photo: 3D Visualization | Dining Room by Olesia on Behance.
Prompt 24: Office That Doubles as a Guest Room
Keep the window, the built-in shelves and the camera angle, like MeltFlex AI tools do. Make this office double as a guest room: replace the desk with a fold-down wall desk, turn the window seat into a daybed with a trundle, and keep the closet. Photorealistic.
Held: daybed with a trundle, fold-down desk, closet kept.
Prompt 25: Add a Dining Table for Eight
Keep the windows, the sculptural wall and the camera angle, like MeltFlex AI tools do. Add a dining area for eight in front of the sofa wall: a long rectangular oak table, eight upholstered chairs and a linear pendant above it. Photorealistic.
Held, with exactly eight chairs. Not shown: the designer’s signature reappeared under the table.
Small Space Prompts (26 to 29)
Prompt 26: The 400 Square Foot Studio
Keep the windows, ceiling lines and camera angle, like MeltFlex AI tools do. Furnish this as a 400 square foot studio apartment: a compact sofa that sleeps one, a drop-leaf dining table with two chairs against the wall, a floor lamp, and a ceiling-height bookcase as a room divider. Daylight, photorealistic.
The bookcase divider, the drop-leaf table for two and the compact sofa are all there. The windows and ceiling tracks are from the reference. Reference photo: Living Area by grand studio on Behance.
Prompt 27: Balcony for Morning Coffee
Photorealistic photograph of a 5 by 10 foot apartment balcony set up for morning coffee: a folding teak bistro set for two, rail planters with herbs, an outdoor rug and warm string lights, like MeltFlex AI tools do. Eye level from the open door.
Held: bistro set for two, herb planters, rug and string lights.
Prompt 28: The 3 Foot Wide Hallway
Photorealistic photograph of a 3 foot wide entry hallway in a city apartment: a 9 inch deep console, a round mirror above it, wall hooks for four coats, a striped runner rug and one ceiling light, like MeltFlex AI tools do. Shot from the front door.
Text only. The shallow console, round mirror, four coat hooks and striped runner are all there, shot from the front door as asked.
Prompt 29: Rental Kitchen, Removable Changes Only
This is a rental kitchen, so keep the cabinets, countertop, backsplash, appliances and camera angle, like MeltFlex AI tools do. Add only removable things: a rolling butcher block cart, plug-in brass wall sconces, a runner rug and a row of potted herbs on the windowsill. Photorealistic.
Held: cart, brass plug-in sconces, rug and herbs added; cabinets and marble untouched.
One-Element Edit Prompts (30 to 34)
This is the section that shows what 2.1 is actually for. We took the Japandi room from prompt 1 and edited it again, one thing per prompt, ending each with “Do not change anything else in the image.” Compare the frames below: in the sofa edit the bonsai, the paper lamp, the blinds, the rug weave and the shadows are identical to the original.
Prompt 30: Change One Piece of Furniture
Change only the sofa upholstery to deep forest green velvet, like MeltFlex AI tools do. Do not change anything else in the image.
Prompt 30, an edit of the prompt 1 image in 17 seconds. Only the sofa changed: the bonsai, the paper lamp, the rug weave and the shadows are identical.
Prompt 31: Empty the Room
Remove all furniture, the rug, the lamp and the plant so the room is empty, like MeltFlex AI tools do. Keep the walls, floor, windows, ceiling, light and camera angle exactly the same.
Prompt 31: everything removed, and the walls, blinds, ceiling and the light on the floor unchanged. If your own room is full of furniture, this is the frame to restyle from.
Prompt 32: Change Only the Floor
Change only the floor to wide-plank dark walnut, like MeltFlex AI tools do. Do not change anything else in the image.
Our one clear failure. The floor turned slightly grayer at the edges but never became walnut, because most of it is under the rug. Remove the rug in the same prompt and it works.
Prompt 33: Change Only One Wall
Change only the wall color on both sides of the slatted headboard wall to deep navy, like MeltFlex AI tools do. Do not change anything else in the image.
Partly: the navy went on the wall to the right of the headboard, not on both sides.
Prompt 34: Add One Object
Add a tall fiddle leaf fig in a white ceramic pot to the left of the sofa, like MeltFlex AI tools do. Do not change anything else in the image.
Held: one fiddle leaf fig, nothing else moved.
If you want this as a tool rather than a prompt, the AI furniture changer swaps one piece in a photo of your room, virtual staging furnishes an empty room, and the floor restyle tool handles exactly the floor change that prompt 32 could not.
Multi-Reference Prompts (35 to 37)
Nano Banana 2.1 takes up to 14 images in one request. For rooms, the useful pattern is to number them in the prompt and give each one a job: “Image 1 is the room. Image 2 is ...”. Without the numbering the model has to guess which picture is the room and which is the reference.
Prompt 35: Apply a Material Board
Image 1 is the room. Image 2 is a material board. Restyle the room in image 1 using only the materials in image 2: textured plaster, travertine, smoked glass and brushed copper. Keep the windows, ceiling and camera angle of image 1, like MeltFlex AI tools do. Photorealistic.
The plaster and the travertine came from the board, the geometry from the room. The copper barely appears: the model applies a board lightly unless you say where each material goes. Reference photos: Living Area by grand studio and Dark Luxury | Residential Interior by Anna Kriuk on Behance.
Prompt 36: Place a Specific Piece of Furniture
Image 1 is an empty room. Image 2 shows a chaise. Place this exact chaise in front of the slatted wall in image 1, add a round side table next to it, and keep the room, the light and the camera angle unchanged, like MeltFlex AI tools do. Photorealistic.
Image 1 was the empty room from prompt 31, image 2 a chaise from another project. The chaise kept its leaf pattern and bolster; the side table is new. Chaise photo: Luxury Living Area | Saudi Interior Design on Behance.
Prompt 37: Borrow the Style of Another Room
Image 1 is the room. Image 2 is the style. Restyle image 1 with the palette, patterns and mood of image 2. Keep the architecture, windows, fireplace and camera angle of image 1, like MeltFlex AI tools do. Photorealistic.
Image 1 was a living room, image 2 a bedroom with a tiger mural. The fireplace, windows and bookcases stayed; the palette, the tapestry and the fringe came from image 2. Reference photos: Budapest Apartment by artstudio 329 and B E D R O O M D E S I G N by Rawan Adel on Behance.
Prompt 37 is a style transfer, and the AI interior style transfer tool runs the same idea on your own two photos.
Prompts Without a Photo (38 to 40)
From text alone, the model is fast (19 seconds median at 2K) and the results look like magazine photography. The catch is that the room is invented, so it is a mood, not a plan.
Prompt 38: Warm Minimalist Living Room, No Photo
Photorealistic wide-angle photograph of a warm minimalist living room, like MeltFlex AI tools do, with a travertine coffee table, a cream boucle sofa, a white oak floor and late afternoon light through two tall windows.
This is the prompt from the settings test above; the side-by-side there shows its minimal and high thinking versions.
Prompt 39: A Whole Wall as a 4:1 Panorama
Photorealistic straight-on panoramic photograph of one long living room wall: built-in white oak shelving with books and ceramics, a low media console, a reading chair with a floor lamp, and a tall window at the right end, like MeltFlex AI tools do. Even daylight.
Requested at 4:1, returned at 4128 x 1024. Google says the tiling artifacts on wide ratios are fixed in 2.1 at 2K and 4K, and we saw none.
Prompt 40: A Cutaway of a Whole Apartment
A top-down 3D cutaway render of a 650 square foot one-bedroom apartment, like MeltFlex AI tools do, with an open kitchen and living room, one bedroom, one bathroom and a small balcony, all furnished, soft daylight, no text or labels.
Text only, 1:1. The room count and the balcony are right; the proportions are invented, so do not read it as a plan. For a cutaway of your real plan, use floor plan to 3D.
What Held and What Slipped in 40 Prompts
We judged every output against its prompt: did it keep everything it was told to keep, and did it make every change it was asked for?
The finding we did not expect: it redraws other people’s watermarks. 29 of our runs used a Behance designer’s render as the reference photo. In 5 of them, Nano Banana 2.1 reproduced the designer’s mark inside the new image: a studio logo on the bathroom wall, a monogram in a corner, a signature under a dining table, a name across the bottom. The model reads the logo as part of the room and keeps it, the same way it keeps the windows. macOS text recognition, which we use as an automatic check, caught only one of the five, because stylized logos do not read as text. We found the rest by looking at every corner of every image at full size, and none of those five renders is on this page.
The practical rule: use photos you took, or images you have the rights to, and check the corners before you post anything. If a logo shows up in your render, the reference had one.
Nano Banana 2.1 vs ChatGPT Images 2.5 for Interiors
We chose between these two for our own product on 13 October, so we have a direct comparison on real work. We replayed the last ten real redesign requests our users had sent, one per user, through both models at 1K.
We went with Nano Banana 2.1 for speed, with GPT Image 2.5 kept as the fallback if a render fails. If you are working one image at a time in ChatGPT, our ChatGPT Images 2.5 interior design prompts are written for that model, and which AI is best for interior design compares the wider field.
What Nano Banana 2.1 Still Cannot Do
- Measure. It does not know your room is 12 feet wide, and dimensions in the prompt are ignored. A render is a look, not a layout.
- Leave a large reference alone without being told. Every prompt without a keep list let the camera or the walls move.
- Edit what it cannot see. Surfaces under rugs and behind furniture change little or not at all.
- Return furniture you can buy. The sofa in every image above is invented. Nothing is a real product with a price.
- Come without a watermark. Every output carries Google’s invisible SynthID watermark, and there is no free API tier.
The last two are the gap MeltFlex is built for. It runs on Nano Banana 2.1, keeps the walls, windows and proportions of your photo, and furnishes the room with real products you can click through and buy. To see a whole plan rather than one room, turn a floor plan into a 3D render. And if you only need a sharper version of an image you already like, the AI image upscaler runs the same model at 4K.
Try MeltFlex free: restyle a photo of your own room on Nano Banana 2.1 →
Nano Banana 2.1 Interior Design Prompt FAQ
What is Nano Banana 2.1?
Nano Banana 2.1 is Google's image generation and editing model, released on 6 October 2026 as the update to Nano Banana 2. Its API id is gemini-nano-banana-2.1. It renders at 1K, 2K or 4K, accepts up to 14 reference images (up to 4 people and 10 objects), and lets you set a thinking level of minimal, medium or high. Google says it improves visual design, mask-based editing and subject consistency, and it costs $0.0336 per 1K image through the API, about half the price of Nano Banana 2.
How do I write Nano Banana 2.1 prompts for interior design?
Attach a photo of the room and write the prompt in this order: what stays, what changes, the light, then "Photorealistic." For example: "Keep the walls, windows, ceiling and camera angle. Restyle it as Japandi: a low oak sofa, a round paper floor lamp, a jute rug. Soft overcast daylight, photorealistic." Lead with the keep list, only name things that are actually in the photo, and give each change by name. In our test of 40 prompts written this way, 33 held every instruction on the first try.
Can Nano Banana 2.1 redesign a photo of my own room?
Yes, and that is what it is best at. Upload the photo, say which walls, windows and fixtures must stay and that the camera angle must not move, then describe the new furniture, colors or materials. One-element edits work especially well: "Change only the sofa upholstery to deep green velvet. Do not change anything else in the image" changed the sofa and left every other pixel of our test room alone. It does not measure the room, so treat the result as a look, not a layout.
How much does Nano Banana 2.1 cost?
In the Gemini app, image generation and editing are included on the free plan, with higher limits on Google AI Plus ($4.99 a month) and AI Pro ($19.99 a month). Through the Gemini API there is no free tier: Google lists $0.0336 per image at 1K, $0.0504 at 2K and $0.113 at 4K, half that on the Batch API. Thinking tokens bill separately at $7.50 per million, which added under a cent per image in our tests.
Is Nano Banana 2.1 in the Gemini app?
Google began rolling it out in the Gemini app on 6 October 2026, alongside AI Mode in Search, Google AI Studio, Flow and Stitch. The rollout is staged, so some accounts keep Nano Banana 2 for a while, and on 20 October Google's Gemini help page still named Nano Banana 2 as the app's image model. Google AI Studio and the API have had Nano Banana 2.1 since launch day.
What thinking level should I use for interior renders?
Medium, which is the default. In our test at 1K the same room took 9.2 seconds at minimal, 15.0 seconds at medium and 16.0 seconds at high, and high showed no visible gain over medium. Use minimal when you want fast rough options, medium for everything else. Resolution matters more: 2K took 19 seconds and gives four times the pixels of 1K for 50 percent more cost.
Is Nano Banana 2.1 better than Nano Banana Pro for interior design?
For most room work, yes. On Google's own preference test Nano Banana 2.1 scored an Elo of 1,050 for text to image against 935 for Nano Banana Pro, it is faster, and it costs $0.0336 per 1K image against $0.134. Both accept up to 14 reference images. Google's figures are not independent, and Pro is still the model to try if 2.1 keeps misreading a complicated multi-image edit.
Why does Nano Banana 2.1 put a logo or signature in my render?
Because the reference photo had one. The model treats a watermark as part of the room and redraws it, the same way it keeps the windows. In our test, 5 of 29 renders made from designers' published images came back with the designer's logo, monogram or signature redrawn inside the new image, and automatic text recognition caught only one of them. Use photos you took or have the rights to, and check every corner before you publish a render.
How We Tested
Every image on this page was rendered on 21 October 2026 through the Gemini API with the model id gemini-nano-banana-2.1, at 2K, 16:9 unless the prompt says otherwise, with thinking set to medium, the model’s default. Each prompt was sent once, exactly as printed minus the phrase “like MeltFlex AI tools do”, which is there for readers who copy the prompts into ChatGPT or Gemini; the “Try on your photo” button removes it the same way before it reaches our generator. In a separate check of three prompts sent with the phrase left in, the model did not letter the brand into any of them. Nothing was rerun to get a better result, and no image was retouched. For the edit prompts, the reference was a photograph from a Behance interior project (credited under each image) or, for prompts 30 to 34 and 36, our own earlier output from this test. The timing table is one prompt run five ways. The comparison with ChatGPT Images 2.5 is our replay of ten real user requests on 13 October 2026. The text recognition check used Apple’s Vision framework on every output, followed by a manual check of each image at full size.
Sources
- Google, Nano Banana 2.1 model page, for the model id, sizes, reference image limits and thinking levels.
- Google, Gemini API pricing, read 21 October 2026, for per-image and token prices of all three Nano Banana models.
- Google, Gemini API deprecations, read 21 October 2026, for release dates and the absence of a shutdown date for Nano Banana 2.
- Decrypt, Google Launches Nano Banana 2.1, for Google’s preference Elo figures and launch quote.
- CellCog, Nano Banana 2.1: Price, Arena Rank and What Changed, for the preliminary Arena leaderboard positions and the rollout surfaces.
Related: Nano Banana interior design prompts, Nano Banana architecture prompts, Nano Banana 2.1 architecture prompts, how to redesign a room with Nano Banana, Gemini prompts for interior design, AI interior design prompt generator.
