Aspect Ratio Calculator

How to use it

1. Enter the width and height in pixels, millimeters or any unit - both sides must use the same one.
2. The simplest integer ratio appears right away, for example 1920 x 1080 becomes 16 : 9.
3. If the ratio matches a common format (1:1, 4:3, 3:2, 16:9, 21:9 and others), it is shown as a badge.
4. To resize, type a new width to get the matching height, or a new height to get the matching width.
5. Use Clear to reset all fields.

Common use cases

• Video and photography - check whether footage matches 16:9, 4:3 or cinematic 21:9 before editing.
• Web and UI design - keep image slots proportional when only one dimension is fixed.
• Print and framing - resize a photo to fit a frame without distortion.
• Social media - convert between square, portrait and landscape crops.

Why it stays private

The ratio math is a greatest-common-divisor calculation in your browser. Nothing is uploaded, nothing is stored, and the page makes no network requests after it loads.

FAQ

Q: My ratio is 16.00 : 9.01 - why is it not recognized as 16:9? A: Recognition compares the reduced integer ratio exactly. Values that are close but not exact stay unrecognized, which is often a hint that the source dimensions are slightly off.

Q: Does the tool work with decimal inputs? A: Yes. The ratio fields round to integers before reducing, and the resize fields accept decimals and return up to two decimal places.

Q: Can I use it for portrait sizes? A: Yes. Portrait formats like 9:16 are in the recognized list; enter the smaller number as the width and the larger as the height.