Free Tool · Architects & Designers
Aspect Ratio Calculator for AI Renders
Pick a ratio and get the exact pixel size an AI render comes out at. Then work out the sheet you are printing on — A0 to A4, ARCH A to E, ANSI — and the DPI a render can actually reach on it.
The main 8 aspect ratios AI render models support
Click a shape to see where it is used and the pixel size it renders at.
1:1 · Square
Social
Instagram square posts and carousels, profile and album artwork
Screen & web
Material and detail studies, thumbnail grids, icon-style previews
Square plates inside a board layout, catalogue and sample sheets
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 1024 × 1024 px | |
| 2K · Creative | 2048 × 2048 px | |
| 4K · Ultra | 4096 × 4096 px |
4:3 · Landscape
Social
Facebook and LinkedIn feed images, Pinterest landscape pins
Screen & web
Classic 4:3 slide decks, iPad full-screen, project documentation
Landscape competition boards, ARCH A/C/E sheets (exact match), Letter and ANSI C/E (3% crop)
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 1024 × 768 px | |
| 2K · Creative | 2048 × 1536 px | |
| 4K · Ultra | 4096 × 3072 px |
3:2 · Landscape
Social
Standard photo-style feed posts, blog and article cover images
Screen & web
Portfolio grids, real estate listing photos, DSLR-native framing
ARCH B/D sheets (exact match), Tabloid and ANSI D (3% crop), A-series (5.7% crop)
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 1024 × 683 px | |
| 2K · Creative | 2048 × 1365 px | |
| 4K · Ultra | 4096 × 2731 px |
16:9 · Landscape
Social
YouTube thumbnails and videos, X/Twitter posts, Facebook shared images
Screen & web
Website hero images, 16:9 presentation slides, laptop and TV full-screen
Wide render strips on a landscape sheet — needs a crop for any A-series format
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 1024 × 576 px | |
| 2K · Creative | 2048 × 1152 px | |
| 4K · Ultra | 4096 × 2304 px |
21:9 · Landscape
Social
Cover and banner images, LinkedIn banner (needs a further crop to 4:1)
Screen & web
Ultrawide monitor wallpapers, cinematic hero strips, full-bleed section headers
Panoramic exhibition boards, wide site sections across a landscape sheet
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 1024 × 439 px | |
| 2K · Creative | 2048 × 878 px | |
| 4K · Ultra | 4096 × 1755 px |
3:4 · Portrait
Social
Instagram portrait feed posts, Facebook portrait images
Screen & web
Portrait tablet viewing, interior height studies, mobile portfolio cards
ARCH A/C/E in portrait (exact match), Letter and ANSI C/E portrait (3% crop)
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 768 × 1024 px | |
| 2K · Creative | 1536 × 2048 px | |
| 4K · Ultra | 3072 × 4096 px |
2:3 · Portrait
Social
Pinterest portrait pins, Instagram portrait posts (6.25% crop to 4:5)
Screen & web
Tall facade studies, portrait urban perspectives, mobile-first article images
ARCH B/D in portrait (exact match), portrait A-series sheets (5.7% crop)
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 683 × 1024 px | |
| 2K · Creative | 1365 × 2048 px | |
| 4K · Ultra | 2731 × 4096 px |
9:16 · Portrait
Social
Instagram Reels and Stories, TikTok, YouTube Shorts
Screen & web
Phone full-screen, vertical video walkthroughs, mobile splash images
Tall facade studies and section strips on a portrait sheet
| Quality | Output pixels | |
|---|---|---|
| 1K · Fast | 576 × 1024 px | |
| 2K · Creative | 1152 × 2048 px | |
| 4K · Ultra | 2304 × 4096 px |
Sheet & DPI calculator
Two questions, both answered here: how many pixels a printed sheet needs, and how big a render you already have can be printed.
—
Use a RenderAI output size:
| DPI | Print size | Inches | Largest sheet covered |
|---|
"Largest sheet covered" is the biggest standard format the image fills completely at that DPI — where the ratios differ, the excess is cropped off.
Print formats and the render ratio each one needs
Click any format to load it into the calculator above.
Metric — ISO A series
Every ISO A sheet is 1:√2 (1.414:1), a ratio no AI image model outputs natively — that proportion is what lets an A3 fold into two A4s, and it sits exactly between 3:2 and 4:3. The fix is a small crop: render at 3:2 and take 5.7% off the long side, or at 4:3 and take 5.7% off the short side.
Imperial — ARCH, ANSI, Letter and Tabloid
The US ARCH series maps exactly onto native AI ratios, unlike the A series: ARCH A, C and E are 3:4 and ARCH B and D are 2:3, so a native render fills the sheet with no crop at all. If you get to choose the sheet, this is the reason to choose ARCH.
| Format | in | Ratio | Native match |
|---|---|---|---|
| ARCH A | 9×12 | 3:4 | 3:4 ✅ exact |
| ARCH B | 12×18 | 2:3 | 2:3 ✅ exact |
| ARCH C | 18×24 | 3:4 | 3:4 ✅ exact |
| ARCH D | 24×36 | 2:3 | 2:3 ✅ exact |
| ARCH E | 36×48 | 3:4 | 3:4 ✅ exact |
| Letter | 8.5×11 | 1:1.294 | 3:4 · crop 2.9% off the long side |
| Tabloid | 11×17 | 1:1.545 | 2:3 · crop 2.9% off the short side |
| ANSI C | 17×22 | 1:1.294 | 3:4 · crop 2.9% off the long side |
| ANSI D | 22×34 | 1:1.545 | 2:3 · crop 2.9% off the short side |
| ANSI E | 34×44 | 1:1.294 | 3:4 · crop 2.9% off the long side |
What print size can a 4K render actually fill?
A 4K render has a 4096 px long side. Spread across a sheet, that is the DPI you get — no upscaling involved.
| Sheet | DPI from a 4K render | DPI from a 2K render |
|---|---|---|
| A0 | 88 | 44 |
| A1 | 124 | 62 |
| A2 | 175 | 88 |
| A3 | 248 | 124 |
| A4 | 350 | 175 |
A 4K render covers A3 and A4 at print quality. A2 sits at the edge, and A1 and A0 need an upscale pass before printing — upscale the render first. Two thresholds are worth keeping in mind: 150 DPI is acceptable for a board read from about a metre away, and 300 DPI is for a document held in the hand. Below 100 DPI the softness is visible at any distance.
Why doesn't ChatGPT respect the aspect ratio I ask for?
Because in ChatGPT the aspect ratio is a request, not a setting. The image model generates at a small set of fixed sizes, and your prompt only nudges it toward one of them — so asking for 16:9 or 4:5 in words does not change the canvas the model draws on.
It is not a bug and it is not something a better prompt fixes. The same applies to Gemini and Nano Banana: the models are good at generating, they just do not hand you a ratio control. The moment a tool exposes the ratio as a parameter — RenderAI does, with the 8 ratios listed above — the problem disappears.
There are two fixes that actually work:
- 1
Aim for a size the model does output
Ask for landscape, portrait or square rather than a specific number, then design around whatever it gives you. Fast, but you do not get to choose the exact proportion.
- 2
Generate large, then crop to the exact ratio
This is the reliable one. The image already has the pixels; you are only choosing which part of the frame survives. Drop the image into Smart Crop and the AI proposes the crops, keeping the subject in frame at full resolution.
Already created an AI image you like, but the aspect ratio is wrong?
Our free Smart Crop tool works on any image regardless of where it came from — ChatGPT, Gemini, Nano Banana, Midjourney, a render engine, or a photo. Use it to fix the aspect ratio automatically.
Fix the aspect ratio →Formats most AI models do not output
Four common destinations sit outside most models' native set. Each one is a render-then-crop job, and the crop is small in three of the four cases.
| Target | Where it is used | Recipe |
|---|---|---|
| 4:5 1080×1350 | Instagram portrait post — the largest format in the feed | Render at 3:4, crop 6.3% off the long side |
| 1.91:1 1200×628 | LinkedIn and Facebook link previews, Open Graph images | Render at 16:9, crop 6.9% off the short side |
| 4:1 1584×396 | LinkedIn profile and company page banner | Render at 21:9, crop 41.7% off the short side |
| 1:√2 A0–A4 | Every ISO A sheet — A4, A3, A2, A1, A0 | Render at 2:3, crop 5.7% off the long side |
Frequently Asked Questions
About aspect ratios, print formats and render resolution
- Because in ChatGPT the aspect ratio is a request, not a setting. Image models generate at a small set of fixed sizes — typically square, landscape and portrait — and the prompt only nudges the model toward one of them. Asking for 16:9 or 4:5 in words does not change the canvas the model draws on, so you get the nearest fixed size instead. There are two real fixes: pick a target that matches one of the sizes the model does output, or generate large and crop to the exact ratio afterwards. Tools with an explicit ratio control, RenderAI included, avoid the problem because the ratio is a parameter rather than a sentence.
- Match the render to the sheet, not the other way round. On a US ARCH sheet you are in luck: ARCH B and ARCH D are exactly 2:3, and ARCH A, C and E are exactly 3:4, so a native render fills the sheet with no crop. On an ISO A sheet — A1 and A0 are the usual competition sizes — every format is 1:√2, which no AI model outputs, so render at 3:2 and crop about 5.7% off the long side. If the render is one plate inside a composed board rather than the whole sheet, 16:9 for the main perspective and 1:1 for detail studies is the combination that lays out most cleanly.
- Not at full print quality in a single pass. A 4K render has a 4096 px long side, which spreads to 124 DPI across an A1 sheet and 88 DPI across an A0. That is acceptable for a board read from a metre away, where 150 DPI is the practical floor, but it is well below the 300 DPI a handheld document needs. A 4K render does cover A3 at 248 DPI and A4 at 350 DPI. For A1 and A0 at print quality, run an upscale pass first: a 2× upscale takes A1 to 248 DPI and a 4× takes A0 to 350 DPI.
- Every ISO A format has the same 1:√2 (1.414:1) proportion, which is what allows an A3 sheet to fold into two A4s. Image models are trained and configured around screen and camera ratios — 16:9, 4:3, 3:2, 1:1 and their portrait forms — and 1:√2 sits between 3:2 (1.5) and 4:3 (1.333), matching neither. It is not a limitation of one model; no mainstream image model outputs it. Render at 3:2 and crop 5.7% off the long side, or at 4:3 and crop 5.7% off the short side. Both lose the same amount of image.
- 150 DPI for a board read from a distance of about a metre — pinned-up competition sheets, exhibition panels, site hoardings. 300 DPI for anything held in the hand and read close up: brochures, tender documents, portfolio prints. 96 DPI is enough for a screen or projector. In pixels: an A1 sheet needs 3508 × 4967 px at 150 DPI and 7016 × 9933 px at 300 DPI. Printing a board at 300 DPI when 150 is the requirement doubles the file size along each side for detail nobody will see at that viewing distance.
- 4:5 portrait, because it occupies the most vertical space in the feed at 1080 × 1350 px. No AI model outputs 4:5 directly, so render at 3:4 and crop 6.25% off the long side. For Reels and Stories use 9:16, which is native. For a carousel where every slide must align, 1:1 is the safest choice and is also native. Avoid posting a 16:9 render straight to the feed: it renders small on a phone and gets scrolled past.
Other Free Tools
From ratios and scales to AI reframing and upscaling — these tools cover the practical workflows architects and interior designers deal with every day.
Next step
Got the ratio? Now render it
In RenderAI the aspect ratio is a setting, not a request. Pick 16:9, 9:16, 3:2 or any of the eight, upload your sketch or plan, and get the render at exactly that shape.
Render at your ratio