Aspect Ratio Cheat Sheet: Cropping for Web, Social and Print

Aspect ratio is width divided by height. It says nothing about resolution — 1600x900 and 800x450 are both 16:9. Getting the ratio right matters because platforms crop to their own ratio whether or not you chose one.

The ratios and where they come from

1:1 (square). Profile pictures, avatars, product grids, app icons. Squares are the safest default for anything that will appear in an unknown layout, because neither dimension dominates.

4:3. The old television and computer-monitor ratio, still standard for many camera sensors in photo mode and for slide decks that need to fill older projectors. Reads as slightly conservative.

3:2. The 35mm film ratio, inherited by most DSLR and mirrorless cameras. If you have not cropped a photo from a real camera, it is almost certainly 3:2.

16:9. Video, YouTube thumbnails, modern presentations, hero banners. The default assumption for anything that plays or spans a full screen.

2:3 (portrait). The vertical flip of 3:2 — portrait photography, book covers, print posters, Pinterest-style feeds.

Center-cropping decides what survives

When you crop to a ratio without moving the crop box, the tool keeps the largest centered rectangle of that ratio and discards the rest. The direction of loss depends on which way the mismatch runs:

Source wider than the target ratio → the left and right edges are cut
Source taller than the target ratio → the top and bottom are cut

For a 3:2 landscape photo cropped to 1:1, that means losing a third of the width. Anything important near the left or right edge disappears. For a portrait cropped to 16:9, you lose most of the vertical frame — heads get cut off, which is why automatic 16:9 crops of portraits look so bad.

The practical rule: shoot and compose wider than your tightest crop. Leave margin around the subject so every downstream ratio has something to discard.

Cropping once for many placements

Rather than exporting one file per platform, define a safe area:

Pick your widest target ratio, usually 16:9, and your tallest, usually 2:3 or 4:5.
Compose so the subject fits inside the intersection of both — a roughly square region in the center.
Export the intersection as your master 1:1, then crop outward to each specific ratio from the original, not from the square.

Cropping from the original each time preserves resolution. Cropping a crop compounds the loss.

Rotation interacts with ratio

Rotating 90° swaps width and height, which inverts the ratio: a 16:9 landscape becomes 9:16 portrait. If a tool applies rotation after cropping, the output ratio is the reciprocal of what you selected. Check the exported dimensions rather than trusting the preview, especially with images that carry EXIF orientation.

Resolution guidance

Ratio and resolution are independent, but there is a floor worth respecting:

Avatars — 400x400 minimum, they get displayed larger than you expect
Social share images — 1200x630 for link previews, which is close to 1.91:1
Full-width hero — 2400px wide for high-DPI screens, then compress hard
Print — think in inches at 300 DPI, not pixels; a 5x7 print at 300 DPI is 1500x2100

Never upscale to hit a minimum. Enlarging a small crop invents pixels and looks worse than a smaller image displayed smaller.

Try it

Image Cropper — crop to 1:1, 4:3, 16:9, 3:2 or 2:3 with rotation and flip, all in the browser
Image Compressor — shrink the file after you have settled the framing
Format Converter — export the final crop as PNG, JPEG or WebP

Related reading: How Image Compression Actually Works explains why cropping before compressing gives you a smaller file than compressing harder.