Aspect Ratio Calculator

Calculate the simplified ratio of width to height and find matching new dimensions without distorting the original aspect ratio.

Aspect ratio

Positive whole numbers up to 10,000,000.

Resize without distortion

Calculate the other dimension while keeping the original aspect ratio.

Rounding to whole pixels can cause a very small deviation.

What this tool does

The aspect ratio describes the relationship between width and height.

A ratio of 16:9 means that 16 parts of width correspond to 9 parts of height.

Images, videos, or screens of different sizes can have the same aspect ratio.

How to use the tool

  1. Enter width and height as positive whole numbers in the same unit, such as pixels.
  2. Select “Calculate” to see the simplified ratio, orientation, and decimal value.
  3. Use “Swap width and height” when you want to reverse the orientation.
  4. In the resize section, enter a new width or height to calculate the matching other dimension.

Useful applications

  • Check aspect ratios for images, videos, monitors, and presentations.
  • Derive matching dimensions for thumbnails and webpages.
  • Change one dimension without stretching or squashing an image or video.

Notes and limitations

  • An aspect ratio has no unit of its own; width and height only need to use the same unit.
  • When only one side changes, the other side must be calculated to keep the image undistorted.
  • Rounding the result to whole pixels can create a minimal deviation from the exact decimal value.
  • The preview shows the shape of the ratio only and does not suggest an exact physical or pixel size.

Frequently asked questions

Why do 1920 × 1080 and 1280 × 720 both have a 16:9 ratio?

Both width and height pairs can be reduced by their greatest common divisor to 16:9. The dimensions are different in size, but their proportion is the same.

More tools in Math & Numbers

View all tools in Math & Numbers