Checked against the source
Instagram square post size
Short answer
Use 1080 × 1080 pixels. Instagram Help says photos are shared at up to 1080 px wide, enlarges those under 320 px, and keeps ratios from 1.91:1 to 3:4 uncropped, so a square needs no crop.
Key takeaways
- A square is the shape in the middle of Instagram's uncropped range: 1:1 sits between 1.91:1 and 3:4, so nothing is cut when you share it (computed).
- At 1080 px wide Instagram does not enlarge or shrink a photo: a bigger file is scaled down to 1080 and a smaller one under 320 px is enlarged to 320, per Instagram Help.
- A 16:9 photo keeps 56% of its area in a square, a 4:5 portrait keeps 80% and a 9:16 frame keeps 56% (computed).
- Across our six test pictures the 1080 × 1080 result was 204 KB to 383 KB as a JPG at quality 0.92.
The size
| What | Value |
|---|---|
| Width | 1080 px |
| Height | 1080 px |
| Aspect ratio | 1:1 |
What the platform publishes
| What | Published value |
|---|---|
| Square | 1080 × 1080 px (1:1, inside the supported range) |
| Width | Up to 1080 px. Wider photos are scaled down to 1080 px; photos under 320 px are enlarged to 320 px |
| Aspect ratios kept uncropped | 1.91:1 to 3:4, i.e. 1080 × 566 to 1080 × 1440 px |
| Outside that range | Cropped to the nearest supported ratio |
Source: Instagram Help: Image resolution of photos you share (checked 2026-10-05)
Resize it now
Scales and center-crops any image to exactly 1080 x 1080 px, in your browser. Nothing is uploaded, there is no file size cap and no daily limit.
Batch is unlimited and free - every image is processed on your device, so there is no queue and no daily cap.
Which shapes Instagram keeps whole (computed)
Instagram Help says photos in the range from 1.91:1 to 3:4 are not cropped and others are cropped to the nearest supported ratio. Applying that to common shapes:
| Photo shape | Kept whole? | Cropped to | Share of the photo kept |
|---|---|---|---|
| 2.35:1 (cinema) | No | 1.91:1 | 81% |
| 1.91:1 | Yes | - | 100% |
| 16:9 (1.78:1) | Yes | - | 100% |
| 3:2 (1.5:1) | Yes | - | 100% |
| 4:3 (1.33:1) | Yes | - | 100% |
| 1:1 | Yes | - | 100% |
| 4:5 (0.8:1) | Yes | - | 100% |
| 3:4 (0.75:1) | Yes | - | 100% |
| 2:3 (0.67:1) | No | 3:4 | 89% |
| 9:16 (0.56:1) | No | 3:4 | 75% |
The sizes at the two ends of the range are 1080 × 566 and 1080 × 1440 pixels. A 9:16 video frame or screenshot loses a quarter of its height when it is shared as a photo.
What a 1080 × 1080 frame does to common photo shapes
The frame is 1:1. A photo of another shape is scaled until it covers the frame and the excess is cut from the center, which is what the resizer on this page does. This is computed from the shapes.
| Photo shape | Share of the photo kept | What is cut |
|---|---|---|
| 16:9 (1920 × 1080) | 56% | The sides |
| 3:2 (3000 × 2000) | 67% | The sides |
| 4:3 (4000 × 3000) | 75% | The sides |
| 1:1 (2000 × 2000) | 100% | Nothing |
| 4:5 (1080 × 1350) | 80% | The top and bottom |
| 9:16 (1080 × 1920) | 56% | The top and bottom |
Computed.
Measured: six pictures through the resizer
The resizer on this page was run in headless Chromium on six test pictures (public domain NASA scans, a PNG graphic and two small pictures made from them): each is scaled to cover 1080 × 1080, drawn on a white background and saved as a JPG at quality 0.92. SSIM compares each result with a Lanczos crop of the same picture made by ffmpeg (1.0 would be identical); it is blank when the frame has an odd side, which ffmpeg's check cannot compare. Other browsers use their own encoders, so sizes can differ.
| Picture | Pixels | Scale | Result | Time | SSIM |
|---|---|---|---|---|---|
| Photo, nearly square | 3840 × 3877 | 0.28× | 383 KB | 17 ms | 0.78 |
| Portrait | 2122 × 2644 | 0.51× | 252 KB | 17 ms | 0.89 |
| Wide document scan | 3827 × 1588 | 0.68× | 304 KB | 17 ms | 0.92 |
| Square PNG graphic | 5380 × 5432 | 0.20× | 274 KB | 14 ms | 0.92 |
| Small portrait (1060 px) | 1060 × 1320 | 1.02× (enlarged) | 210 KB | 20 ms | 0.96 |
| Small landscape (640 px) | 640 × 480 | 2.25× (enlarged) | 204 KB | 17 ms | 0.97 |
A scale above 1 enlarges the picture to fill the frame; enlarging adds no detail, so start from a file at least as large as the frame.
Detail decides the file size (measured)
The same frame holds 1.17 megapixels whatever the picture, but the JPG size follows the detail in it. Bits per pixel is the file size in bits divided by the number of pixels in the frame.
| Picture | Result | Bits per pixel |
|---|---|---|
| Photo, nearly square | 383 KB | 2.63 |
| Portrait | 252 KB | 1.73 |
| Wide document scan | 304 KB | 2.09 |
| Square PNG graphic | 274 KB | 1.88 |
| Small portrait (1060 px) | 210 KB | 1.44 |
| Small landscape (640 px) | 204 KB | 1.40 |
Smooth areas and flat color compress to a fraction of what fine detail needs; a photograph full of texture is the expensive case. If a size limit matters, check your own picture, not an average.
Using the Instagram square post size
- Start from a file at least 1080 × 1080 pixels so nothing is enlarged.
- Keep faces, logos and text away from the edges; every crop above cuts the edges.
- Check the platform's own page before you rely on a figure; sizes change.
- The resizer above does the crop and the JPG in your browser; nothing is uploaded.
Frequently asked questions
Does a square post get cropped?
No. Instagram Help lists 1.91:1 to 3:4 as the range kept uncropped, and 1:1 is inside it.
Is 1080 × 1080 or 1080 × 1350 better?
Both are inside the range. 1080 × 1350 (4:5) takes more of the screen; the square is the choice when the image must work in more than one place.
How much of a 16:9 photo is kept in 1080 × 1080?
56% of its area (computed).
What is the aspect ratio of 1080 × 1080?
1:1, 1.17 megapixels.
How big will the file be?
Our six test pictures came out between 204 KB and 383 KB as JPGs at quality 0.92; detailed photographs are the large end.
Is my picture uploaded?
No. The resizer runs in your browser.
Other Instagram sizes
Sources
- Instagram Help: Image resolution of photos you share (checked 2026-10-05)
- Wikimedia Commons: Buzz salutes the U.S. Flag (NASA, public domain), one of the test pictures (checked 2026-10-10)
- MDN: HTMLCanvasElement.toBlob() (JPEG quality) (checked 2026-10-10)
