Find the aspect ratio of an image or screen, and work out the matching height or width when you resize. Enter a width and height, then a new width or height to keep the same proportions.
| Decimal ratio | – |
| Orientation | – |
How it works
The aspect ratio is the width divided by the height, simplified by dividing both by their greatest common divisor. Common ratios are 16:9 for widescreen video, 4:3 for older screens, 1:1 for square images and 9:16 for vertical video. To resize, new height = new width × height ÷ width, and the reverse for a new width.
Example
1920 by 1080 is 16:9. Resizing to a width of 1280 keeps the ratio with a height of 720.
Frequently asked questions
What is 16:9?
A widescreen ratio: 16 units wide for every 9 tall. It is the standard for most video and monitors.
How do I resize without stretching?
Change one side and calculate the other with the same ratio, as this tool does.
What aspect ratio is a phone screen?
Many modern phones are taller than 16:9 when held upright. Check your device.
More free tools: CSS unit converter · Color converter · All free tools
This calculator is for general use.