How is the ratio simplified?

The width and height are divided by their greatest common divisor, so 1920×1080 becomes 16:9 and 1280×720 also becomes 16:9.

What if the height isn't a whole number?

The resized height is shown with up to two decimals. For example, a target width of 1000 at 16:9 gives 562.5.

Is my data sent anywhere?

No. All calculations happen in your browser; nothing is uploaded.

What are the most common aspect ratios?

16:9 is the standard for most video and displays, 4:3 is the older television and monitor shape, 21:9 is ultrawide, 3:2 is common for cameras, and 1:1 is a square. Enter any width and height and the tool reduces it to whichever ratio applies.

Aspect Ratio Calculator

Find the simplified aspect ratio of any width and height — like 16:9 — and resize to a new width while keeping the same ratio.

Width

Height

Aspect ratio16:9

Resize keeping this ratio

Target width

Target height

How to use it

Enter a width and a height and the simplified aspect ratio appears on the spot, updating as you type. Then, in the resize section, type a new target width and the matching height that keeps the same shape is worked out for you. Everything runs in your browser, so nothing is uploaded. The ratio is simplified by dividing the width and height by their greatest common divisor, which is why 1920 by 1080 and 1280 by 720 both reduce to the familiar 16:9. This is the standard behind most modern video and displays; other common shapes are 4:3 for older screens, 21:9 for ultrawide monitors, 3:2 for many cameras, and 1:1 for square social posts. Seeing the reduced form makes it easy to tell at a glance whether two sizes share the same proportions. The resize half is for scaling without distortion. Once a ratio is set, enter the width you want and the tool returns the height that preserves it, so your image or video keeps its shape instead of being stretched. If that height does not land on a whole number it is shown with decimals — a 1000-pixel-wide frame at 16:9 is 562.5 pixels tall — and if you enter sizes that are not whole numbers the ratio falls back to a decimal form like 1.85:1. As a worked example, a 3840 by 2160 image is 4K and reduces to 16:9; ask for a width of 1920 and you get a height of 1080, the same shape at half the size. A 1080 by 1080 image reduces to 1:1, confirming it is perfectly square. Working out aspect ratios is a routine step when exporting video, cropping images to a target shape, laying out responsive designs, and choosing a monitor or television size. Because the whole calculation happens on your device it stays private, and both the ratio and the resized height update instantly as you experiment.

Frequently asked questions

How is the ratio simplified?: The width and height are divided by their greatest common divisor, so 1920×1080 becomes 16:9 and 1280×720 also becomes 16:9.
What if the height isn't a whole number?: The resized height is shown with up to two decimals. For example, a target width of 1000 at 16:9 gives 562.5.
Is my data sent anywhere?: No. All calculations happen in your browser; nothing is uploaded.
What are the most common aspect ratios?: 16:9 is the standard for most video and displays, 4:3 is the older television and monitor shape, 21:9 is ultrawide, 3:2 is common for cameras, and 1:1 is a square. Enter any width and height and the tool reduces it to whichever ratio applies.