Green 3D nested rectangles in different ratios with an arrow

Aspect Ratio Calculator

Pick a ratio and one side, get the other in pixels — or enter a width and height and find out what ratio it is. Free, no login.

Aspect ratio

9:16 — TikTok, Reels, Shorts, Stories

Width (px)Height (px)

1080 × 1920 px

9:16 — 0.563:1

Common sizes at this ratio

540 × 960
720 × 1280
1080 × 1920
1440 × 2560
2160 × 3840

Check the size against a platform's spec →

Frequently asked questions

What is an aspect ratio?

The width of an image or video compared to its height — 16:9 is sixteen units wide for every nine high. 1920 × 1080 and 1280 × 720 are both 16:9; the ratio stays the same as the pixels scale.

Which ratio do I need for each platform?

9:16 for TikTok, Reels, Shorts and Stories; 16:9 for regular YouTube; 1:1 for square posts; 4:5 for Instagram portrait posts; 3:4 to match the Instagram grid; 2:3 for Pinterest. The presets are labelled with these.

How do I convert a ratio to pixels?

Pick the ratio, enter the width or height you have, and the other side is worked out and rounded to whole pixels. The common sizes at that ratio are listed under the result.

What ratio is my video?

Switch to "What ratio is this?", enter the width and height, and it's reduced to the simplest form — 1920 × 1080 becomes 16:9 — and matched to a platform preset if it's one.