Aspect Ratio Calculator
Find an image or screen's aspect ratio and resize it without distortion.
About the Aspect Ratio Calculator
Enter the original width and height to get the aspect ratio in lowest terms and as a decimal. Enter a new width (or a new height) to get the matching other side, so an image or video keeps its shape.
Common ratios: 16:9 (HD video, most monitors), 4:3 (older screens, many photos), 3:2 (35 mm photos), 21:9 (ultrawide) and 9:16 (vertical video). To resize, keep width ÷ height constant.
The formula
New height = new width × height ÷ width
Worked example
A 1920 × 1080 image resized to 1280 wide
- Highest common factor of 1920 and 1080: 120
- 1920 ÷ 120 : 1080 ÷ 120 = 16:9
- New height: 1280 × 1080 ÷ 1920 = 720 px
Questions people ask
Is 1920 × 1080 16:9?
Yes: both divide by 120.
What about 1366 × 768?
It's very close to 16:9 (683:384).
What size is a 9:16 vertical video?
Usually 1080 × 1920 px, the 16:9 size turned on its side.