Try the Aspect Ratio Calculator
Calculate the aspect ratio of any width and height, and resize while keeping proportions. Includes presets for 16:9, 4:3, 1:1, 9:16 and 21:9.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
What is the Aspect Ratio Calculator?
The aspect ratio of an image, video or screen is the proportional relationship between its width and height, written like 16:9. When you resize without preserving the ratio the picture stretches or squashes. This calculator finds the simplified ratio of any dimensions and works out the missing side when you change one.
Enter a width and height to see the ratio and its decimal value, then type a new width or height to get the matching dimension. One-click presets cover the most common formats — 16:9 widescreen, 4:3, 1:1 square, 9:16 vertical video, 3:2 photos and 21:9 ultrawide — for designers, video editors, developers and social media creators.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
1920×1080 becomes 16:9 automatically.
Type one new dimension to get the other.
16:9, 4:3, 1:1, 9:16, 3:2 and 21:9.
Images, video, screens, canvas sizes and print.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
Video editors and creators
Export for YouTube, TikTok and Instagram without black bars.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This utility | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What is the aspect ratio of 1920×1080?
16:9.
How do I resize an image without stretching?
Keep the same ratio: multiply or divide both sides by the same factor.
What is the 4:3 ratio used for?
Older TVs and monitors, and many tablets and photos.
What ratio is vertical video?
9:16.
Can I use decimals?
Yes, but whole pixel values are recommended.
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Try the Aspect Ratio Calculator now
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