Work out any video aspect ratio or size
Enter a resolution to get its simplified ratio and the nearest standard shape. Or pick a ratio and one side to get the other, rounded to an even number so H.264 and H.265 encoders accept it.
A video's aspect ratio is its width divided by its height, written in lowest terms: 1920×1080 is 16:9 (1.778), 1080×1920 is 9:16 and 1080×1350 is 4:5. To find a missing side, divide the width by the ratio or multiply the height by it; for 16:9 at 1280 wide that's 720. Round to an even number, because most video encoders need even dimensions.
3 steps, a few seconds
Choose a mode
Find the ratio from a size, or find a missing side from a ratio.
Enter the numbers
Type a width and height, or tap a preset like 1080p or vertical 1080×1920.
Read the result
See the ratio, decimal, nearest standard shape and a scaled preview.
What the Video Aspect Ratio Calculator does
Simplified ratio
1920×1080 becomes 16:9, 2560×1080 becomes 64:27, with the decimal beside it.
Nearest standard
Compares against 16:9, 9:16, 1:1, 4:5, 4:3, 21:9 and 2.39:1 and shows how far off you are.
Even-number rounding
Missing sides are rounded to an even pixel count, which H.264 and H.265 need.
Shape preview
A scaled box shows the frame shape at a glance.
Resolution presets
720p, 1080p, 1440p, 4K, vertical, square and 4:5 in one tap.
Free
No account, works offline once the page loads.
- Find the ratio
- Width and height in pixels to a simplified ratio, decimal and nearest common ratio
- Find a side
- 16:9, 9:16, 1:1, 4:5, 4:3, 21:9, 2.39:1 or a custom ratio, plus a width or height
- Rounding
- Missing side rounded to the nearest even number; the exact value is shown too
- Presets
- 1280×720, 1920×1080, 2560×1440, 3840×2160, 1080×1920, 1080×1080, 1080×1350
- Cost and privacy
- Free, no sign-up; the math runs in your browser
Need more than a free tool?
QuickVeed's AI studio does the heavy lifting. New accounts get a 14-day trial with 75 credits, no card needed.
Questions about the Video Aspect Ratio Calculator
What aspect ratio is 1920×1080?
What's the difference between 16:9 and 9:16?
How do I calculate the height for a 16:9 video?
Why should video dimensions be even numbers?
Is 21:9 the same as 2.39:1?
What ratio should I use for social media?
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