Aspect ratios explained: crop, pad or stretch?
An aspect ratio is the shape of an image: its width divided by its height. Most of the frustration of "my photo got cut off" comes from putting an image of one shape into a frame of another.
The ratios you will actually meet
| Ratio | Shape | Where it comes from |
|---|---|---|
| 4:3 | 1.33 wide | Almost every phone camera's default photo |
| 3:2 | 1.5 wide | DSLR and mirrorless cameras; 4×6 inch prints |
| 16:9 | 1.78 wide | Video, TV, laptop screens, YouTube thumbnails |
| 1:1 | Square | Profile pictures, product photos, Instagram grid |
| 4:5 | 0.8 (portrait) | Instagram's tallest feed post, 1080×1350 |
| 9:16 | 0.56 (portrait) | Stories, Reels, TikTok, Shorts — a phone screen held upright |
The ratio says nothing about resolution. A 1080×1080 image and a 4000×4000 image are both 1:1. Our social media sizes guide lists the exact pixel sizes each platform wants.
Working out a ratio
Divide width by height and compare. 4032×3024 (a typical phone photo) is 1.333, so 4:3. 6000×4000 is 1.5, so 3:2. If the number is below 1, the image is portrait.
The difference between 4:3 and 3:2 looks small but is not. Printing a 4:3 phone photo on 6×4 inch paper (3:2) means losing about 11% of the picture from the top and bottom, which is exactly why heads get clipped in prints.
The only three ways to change shape
There is no fourth option. Every tool, app and website that fits an image to a frame is doing one of these, and knowing which one explains most surprises.
1. Crop: cut some of it off
Keep the part that matters and throw the edges away. The image stays sharp and undistorted, and you lose content.
The loss is predictable. Taking a 4000×3000 photo (4:3) to 16:9 keeps the full width and cuts the height to 2250, losing a quarter of the picture. Taking the same photo to 9:16 for a story keeps the full height and cuts the width to 1688, losing almost 58% of it.
Crop when the subject sits comfortably inside the new frame. Use the image cropper with a locked ratio — for example 16:9 or 1:1 — and drag the frame to choose what stays.
2. Pad: add space around it
Keep every pixel and add bars, a colour or a blurred copy around it to fill the new shape. Nothing is lost and nothing is distorted, but the image is smaller within the frame.
Pad when you cannot afford to lose anything: a group photo where someone is at the edge, a screenshot, a product that fills the frame, artwork. The canvas resizer does this, and its make square preset is the quickest way to post a full photo to a square slot.
3. Stretch: squash it to fit
Change the width and height by different amounts. Nothing is lost and there are no bars, and everything in the picture is visibly distorted. Faces go wide or thin, circles become ovals.
Stretching is almost never what you want for a photo. It is only acceptable for textures, backgrounds and abstract patterns where nobody can tell. Our image resizer keeps the ratio locked by default for this reason; unticking Keep aspect ratio is how you ask for a stretch.
What platforms do if you do nothing
Upload the wrong shape and the platform makes the choice for you. Instagram crops feed posts to the nearest ratio it allows. YouTube pads with black bars. Some profile-picture uploaders stretch. Most crop from the centre, which is fine for a landscape and bad for a portrait whose face is in the top third.
Doing it yourself first is the only way to control what gets lost. It also means you upload an image at the exact pixel size the platform wants, so it is not resampled again on the way in.
A quick decision rule
- Subject in the middle, room around it → crop.
- Important content right up to the edges → pad.
- A texture or background nobody will inspect → stretch is acceptable.