Crop a photo to the right aspect ratio

What an aspect ratio actually is

An aspect ratio is the proportion between an image's width and its height, written as two numbers separated by a colon. A 1:1 image is a perfect square; 16:9 is a wide rectangle like a TV screen; 4:5 is a tall portrait rectangle. The ratio says nothing about how many pixels the image has. A 1:1 photo can be 200 × 200 px or 2000 × 2000 px and both are still square. What matters for fitting a slot is the shape, and the shape is the ratio.

To work out a ratio from pixels, divide the width by the height and simplify. A 1920 × 1080 photo divides to 1.78, which is 16:9. A 1080 × 1350 photo divides to 0.8, which is 4:5. You rarely need to do this by hand, because the crop tool lets you lock to a named ratio and shows you the box, but knowing the maths helps when a form quotes an odd size and you need to recognise its shape.

Crop versus resize, and when to use each

Cropping and resizing both change an image, but they do different jobs, and using the wrong one is the usual cause of a stretched or squashed photo. Cropping cuts pixels away from the edges to change the framing or the shape, and the part you keep stays at its original quality. Resizing scales the whole image up or down, keeping everything in frame but changing the pixel count.

• Crop when the shape is wrong: you have a tall portrait but need a square, or a wide landscape but need a 4:5 post. Cropping removes the extra edges and never distorts what remains.
• Resize when the shape is already right but the file is too big or too small in pixels, for example a correctly-shaped photo that a form wants delivered at exactly 600 × 600 px. Use resize in pixels for that.
• Often you do both, in order: crop to the target ratio first, then resize the cropped result to the exact pixel size the destination asks for.

A common mistake is forcing a resize to do a crop's job. If you take a 4:3 photo and resize it into a 1:1 box, the image stretches and faces look unnaturally wide. Crop to 1:1 first, then resize, and the proportions stay honest. If your photo is also rotated the wrong way from the camera, straighten it with the rotate tool before cropping so your frame lines up with the horizon.

Common aspect ratios and where they are used

A handful of ratios cover almost everything you will be asked for. The table maps each to where it shows up so you can pick the right one before you start dragging the crop box.

Cropping for social posts

Social platforms each preview your image in a fixed shape, then crop whatever does not fit — usually badly, and usually around someone's face. Cropping to the platform's ratio yourself before you upload means you decide the framing instead of the algorithm.

Feed posts

For Instagram and Facebook, 4:5 is the tallest portrait shape the feed will show in full, so it gives your image the most screen height without being cropped. 1:1 square is the safest all-rounder and the shape the grid thumbnail uses. Avoid uploading a wider-than-square landscape to a portrait-first feed unless you have deliberately cropped it.

Stories, Reels and Shorts

Vertical video and story formats are 9:16, the full height of a phone held upright. If you crop a normal photo to 9:16 you will lose a lot of the sides, so leave headroom and keep your subject centred. Crop to 9:16 with the crop tool, then check the important parts are clear of the top and bottom where buttons and captions overlay.

• Square (1:1): Instagram grid, generic profile and product shots, safe everywhere.
• Portrait (4:5): the biggest feed post on Instagram and Facebook before they crop it.
• Vertical (9:16): Stories, Reels, TikTok and YouTube Shorts.
• Wide (16:9): YouTube thumbnails and link-preview cards.

Cropping for print

Print is unforgiving about ratio because paper comes in fixed sizes. A standard 4 × 6 inch print is 3:2, but most phone cameras shoot 4:3, so a phone photo sent straight to a 4 × 6 lab gets auto-cropped, and the lab decides what to cut. Crop to the print's ratio yourself first and you keep control of the framing.

Resolution still matters for print even after the crop is right. Aim for about 300 pixels per inch of the final print, so a 4 × 6 wants roughly 1200 × 1800 px. If your cropped image is smaller than that, it may look soft on paper. Set the physical print resolution with the DPI tool if your lab asks for a specific DPI, and read the resize in centimetres guide for converting between cm, inches and pixels.

Cropping for ID, passport and profile pictures

Document photos are the strictest cropping job because the ratio, the head size within the frame and the margins are all specified. A passport photo is typically a tall portrait: 35 × 45 mm in much of the world (close to a 7:9 ratio) and 2 × 2 inches (a 1:1 square) in the United States, with rules about how much of the frame your face fills. Crop so the head and a little shoulder are centred, leave even space above the hair, and do not cut the chin or the top of the head.

Round profile pictures

Most platforms ask for a square upload and then mask it into a circle, so the corners of your square are never shown. That means you should keep the subject centred and away from the corners. If you want to preview the exact round result, or export a true round avatar with a transparent background, use the circle crop tool. It crops to a circle and saves a PNG so the corners stay transparent instead of turning white.

1. Check the required ratio and head-size rules for the document or platform.
2. Open the photo in the crop tool and lock to the matching ratio (1:1 for a US passport or a profile picture, a tall portrait for most other passports).
3. Frame the face centred with even headroom, then crop.
4. For a round avatar, run the square result through the circle crop.
5. Resize to the exact pixel size and compress to any KB limit the portal sets.

Cropping without losing quality

Cropping itself is close to lossless, because you are discarding pixels at the edges and the pixels you keep are untouched. Quality loss creeps in from two other places: re-encoding and over-zooming.

• Re-encoding: saving a JPG re-compresses it, and each save loses a little detail. Crop in one pass and export once rather than cropping, saving, reopening and cropping again. If you need a format change too, do the conversion in the same step rather than round-tripping the file.
• Over-zooming: cropping to a tiny region of a photo and then enlarging it back up forces the software to invent pixels, which looks soft and blocky. Start with the highest-resolution original you have so a tight crop still leaves enough real detail.
• Format choice: keep transparency by exporting a crop as PNG; for a flat photo headed to a form, a high-quality JPG keeps the file small. The crop does not decide the format — your export setting does.

After cropping, you usually still need to hit a size target. Resize the cropped image to the exact pixels the destination wants, then compress to its KB limit with the compress to KB tool so the upload is accepted on the first try.