Aspect Ratio Calculator
Enter any width and height in pixels to get the simplified aspect ratio, or pick a ratio — 16:9 in px, 4:3, 3:2 in pixels — and let the calculator work out the matching dimensions.
Choosing a ratio recalculates the height from the width you entered.
How to calculate an aspect ratio
Divide both dimensions by their greatest common divisor. For 1920 × 1080 the GCD is 120, which reduces to 16:9. For 1350 × 2250 the GCD is 450, giving 3:5.
Some dimensions do not reduce to tidy whole numbers, in which case the decimal form is more useful: 1.91:1 for a link preview image, or 2.39:1 for anamorphic cinema.
Aspect ratios in pixels
16:9 is the video standard — 1920 × 1080, 2560 × 1440 and 3840 × 2160 all share it. 4:3 is the classic display and camera ratio. 3:2 comes from 35 mm film and is what most interchangeable-lens cameras still shoot. 1:1 is the square social post, and 9:16 the vertical video format.
Print sizes have their own ratios, and they rarely match camera ratios. An 8 × 10 print is 4:5, so a 3:2 photograph must be cropped to fit it.
Reference table
| Ratio | Used for | Example dimensions |
|---|---|---|
| 16:9 | Video, monitors | 1920 × 1080, 3840 × 2160 |
| 9:16 | Stories, Reels, Shorts | 1080 × 1920 |
| 4:3 | Classic displays, tablets | 2048 × 1536 |
| 3:2 | 35 mm photography | 6000 × 4000 |
| 1:1 | Square social posts | 1080 × 1080 |
| 4:5 | Instagram portrait, 8 × 10 print | 1080 × 1350 |
| 21:9 | Ultrawide monitors | 2560 × 1080 |
| 1.91:1 | Link preview images | 1200 × 630 |
Frequently asked questions
What is 16:9 in px?
16:9 is a ratio rather than a size, so it covers 1280 × 720, 1920 × 1080, 2560 × 1440 and 3840 × 2160 alike. Any width divided by 16 and multiplied by 9 gives the matching height in px.
What is 3:4 pixel dimensions?
3:4 is portrait — 1536 × 2048, 1200 × 1600 or 900 × 1200. Multiply the width by 4 and divide by 3 to get the height.
What aspect ratio is 1350 pixels by 2250 pixels?
1350 × 2250 reduces to 3:5, a portrait ratio. Both numbers divide by 450.
What is the aspect ratio of 1366 × 768?
683:384 — not 16:9. Sixteen-ninths of 768 is 1365.33, so the common laptop panel is a hundredth wider than the video ratio; the decimal form, 1.78:1, is the honest way to write it.
What is 3:4 in pixels?
3:4 is portrait orientation — 1536 × 2048 or 1200 × 1600, for example. Multiply the width by 4 and divide by 3 to get the height.