Tools
Aspect ratio calculator for video and images
Enter a width and height, or drop an image to read its real dimensions, and get the simplified ratio, the decimal ratio, and the closest standard format.
What it gives you
- Simplified ratio — 1920×1080 reduces to 16:9 rather than leaving you to work it out.
- Decimal ratio — the number cinema and camera specs are usually quoted in, such as 1.778:1 or 2.39:1.
- Closest standard — tells you when a size is exactly a known format and when it is merely close.
Resize without breaking the frame
Lock the ratio and changing one dimension updates the other, so you can scale to a target width without distorting the image. Unlock it to set both freely when you deliberately want a different shape. Presets cover 1:1, 4:5, 9:16, 16:9, 3:2, 4:3, 1.85:1, 2.00:1 and 2.39:1.
Reading an image
Drop an image onto the tool, or click to choose one, and its real pixel dimensions are read directly in your browser. The file is never uploaded, never sent to a server, and never stored — the calculator only needs the numbers.
How it works
Enter or drop
Type a width and height, or drop an image to read its dimensions automatically.
Lock the ratio
With the lock on, changing one side scales the other so the frame stays true.
Pick a target
Choose a preset such as 9:16 or 2.39:1 and the matching dimensions are worked out for you.
FAQ
FAQ
Is my image uploaded when I drop it in?
No. The image is read locally in your browser to get its pixel dimensions. Nothing is uploaded, transmitted, or stored.
What is the difference between 16:9 and 1.78:1?
They are the same shape expressed differently. 16:9 is the simplified integer ratio; 1.78:1 is the same value as a decimal, which is how cinema and camera specifications are usually written.
Which ratio should I use for social video?
9:16 for full-screen vertical such as Reels and Stories, 4:5 for the tallest in-feed post most platforms allow, 1:1 for square, and 16:9 for horizontal players. Check the platform's current guidance, as these change.