Aspect Ratio CalculatorWhat is an aspect ratio?
An aspect ratio is the proportional relationship between an image's or screen's width and its height, written as width:height. A 1920 × 1080 video and a 1280 × 720 video are different sizes but share the same 16:9 shape, so one scales to the other without stretching.
How to calculate aspect ratio
Find the greatest common divisor (GCD) of the width and height, then divide both by it. For 1920 × 1080 the GCD is 120: 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, giving 16:9. To resize, use new height = new width × H ÷ W.
Common aspect ratios
| Ratio | Typical use | Example size |
|---|---|---|
| 16:9 | YouTube, HD/4K TV, monitors | 1920 × 1080, 3840 × 2160 |
| 9:16 | TikTok, Instagram Reels, YouTube Shorts | 1080 × 1920 |
| 4:3 | Classic TV, iPad, many phone cameras | 1024 × 768 |
| 3:2 | DSLR and mirrorless photos, 4×6 prints | 6000 × 4000 |
| 1:1 | Instagram square posts, profile pictures | 1080 × 1080 |
| 4:5 | Instagram portrait posts | 1080 × 1350 |
| 16:10 | MacBooks and many laptops | 1440 × 900, 2560 × 1600 |
| 21:9 | Ultrawide monitors, cinema | 3440 × 1440 |
FAQ
How do I calculate an aspect ratio?
Divide the width and the height by their greatest common divisor. For 1920 × 1080 the GCD is 120, so the ratio is 16:9. Type any size in box 1 to do it instantly.
What aspect ratio is 1920 × 1080?
1920 × 1080 (Full HD) is 16:9, the standard ratio for YouTube, TVs and most monitors.
How do I resize an image without distorting it?
Keep the same ratio: new height = new width × original height ÷ original width. Enter the ratio and one new side in box 2 and the other side is filled in.
Is my image uploaded?
No. The image is read by your browser only to get its width and height. Nothing is sent to a server.
What is the aspect ratio for TikTok, Reels and Shorts?
Vertical video uses 9:16, usually 1080 × 1920 pixels.
Why is 1366 × 768 not exactly 16:9?
1366 × 768 reduces to 683:384, which is about 0.05% off 16:9. Screens like this are sold as 16:9 because they are so close; the calculator shows the closest standard ratio for you.