Aspect ratios explained: where 1:1, 4:5, 3:2, 16:9 and 9:16 belong
A ratio is a shape, not a size. What gets cut when the ratio your camera shoots differs from the one a platform wants, in numbers.
Updated 2026-09-10
A ratio is the relationship between width and height. 1080x1080 is 1:1, and so is 500x500 — different sizes, same shape. When matching a spec, size can be scaled or filled, but a different ratio always means cutting something off or adding a margin. That is why ratio comes before size.
| Ratio | Shape | Where it comes from | Where it goes |
|---|---|---|---|
| 1:1 | Square | — | Instagram feed, profile pictures, app icons |
| 4:5 | Slightly tall | — | Instagram portrait posts |
| 3:4 and 4:3 | Tall and wide | Phone default photos, iPad | General posts, documents |
| 2:3 and 3:2 | Tall and wide | DSLRs, mirrorless, 35mm film | 4x6 prints, photo printing |
| 16:9 | Widescreen | Video, monitors, TV | YouTube thumbnails, slides, link cards |
| 9:16 | Full-screen vertical | Phone screens | Reels, Shorts, TikTok, Stories |
| 1.91:1 | Wide card | — | Link previews (OG), Instagram landscape posts |
| 2:1 | Wide card | — | X large cards, banners |
The camera shoots 4:3; nowhere wants 4:3
Phones shoot 4:3 by default (3:4 held upright). But the Instagram feed wants 4:5, Reels 9:16, YouTube thumbnails 16:9, and prints 3:2. Almost nowhere accepts 4:3 as is. So a photo nearly always changes ratio before it is posted, and every change cuts something off.
How much is lost can be calculated. Take a 4:3 photo at 4032x3024. Crop to 16:9 and 25 percent of the height goes. Crop to 1:1 and 25 percent of the width goes. Crop to 9:16 and 58 percent of the width goes, leaving a 1701-pixel strip. The further apart the ratios, the more is lost.
| 4:3 original to this ratio | What remains | What is cut |
|---|---|---|
| 3:2 | 100% width x 89% height | 11% off top and bottom |
| 16:9 | 100% width x 75% height | 25% off top and bottom |
| 1:1 | 75% width x 100% height | 25% off the sides |
| 4:5 (from an upright 3:4) | 100% width x 94% height | 6% off top and bottom |
| 9:16 | 42% width x 100% height | 58% off the sides |
Crop, fill, stretch
There are three ways to change a ratio. Crop discards what is outside. Fill keeps the photo and adds background where it falls short. Stretch pulls the photo in one direction. The third is never acceptable: faces go wide or long, and viewers feel something is wrong without knowing what.
Choosing between crop and fill comes down to whether there is anything you can afford to lose. Losing some sky from a landscape is fine; losing the people at either end of a group photo is not. That case is fill. A 4:3 group photo posted to a 9:16 Story loses more than half if cropped, but keeps everyone if filled, with background above and below.
Why prints come back cropped
4x6 photo paper is 3:2. Phone photos are 4:3. Hand one over as is and the machine trims 11 percent off the top and bottom to fit. A photo with little space above the head comes back with the crown cut off. Crop to 3:2 yourself before ordering, or fill to 3:2 if you want margins instead.