Aspect Ratio Calculator
Work out a ratio like 16:9 and the matching width or height for any new size.
How to use: Enter the original width and height to see the ratio, then type a new width (or height) and the other value is calculated for you.
How to use the Aspect Ratio Calculator
Aspect ratio is the proportional relationship between width and height. A 1920 × 1080 pixel video and a 1280 × 720 thumbnail are both 16:9, so one can be scaled to the other without stretching or black bars. Getting the ratio right matters for photos, videos, slides, screens, print layouts and responsive web images.
Type the original width and height and the calculator reduces them to the simplest whole-number ratio by dividing both by their greatest common divisor. It also shows the decimal ratio and, when the result is within two percent of a well-known format, the closest standard such as 16:9, 4:3, 3:2 or 21:9. A small box previews the shape.
To resize while keeping proportions, enter a new width and the matching height appears, or enter a new height and the width updates instead. Values are rounded to two decimal places; for pixels, round to the nearest whole number. The quick buttons fill in popular sizes for high-definition video, social media posts, stories and link previews.
Because the maths is simple division, the calculator works for any unit, including inches, centimetres and millimetres.
Frequently asked questions
What aspect ratio is 1920 × 1080?
It is 16:9, the standard for HD and 4K video, most monitors and TVs.
How do I calculate the height for a new width?
Multiply the new width by the original height and divide by the original width.
Why is my ratio something odd like 683:384?
Some screen sizes are not exactly a standard ratio. The closest-standard result tells you which common format it is nearest to.