A little clarity for every image

Aspect Ratio Calculator

Calculate an image's aspect ratio from its width and height, or enter a ratio and one dimension to find the other. Preview common and custom ratios.

1Enter your dimensions

Crop or pad an image to this ratio →
Read pixel dimensions from an image

Optional. You can also enter the pixels directly.

Your result

Enter your dimensions to calculate.

This calculation changes no image pixels and makes no assumption about image quality.

Results are kept in this browser for up to 24 hours.

Simplify a width-to-height ratio or calculate a matching edge. Keep the shape you need when preparing a crop, print or website image.

Keep proportions explicit

  1. Enter width and height in the same unit to simplify their ratio.
  2. Choose the desired ratio or change one edge to calculate the other.
  3. Compare the shape preview, orientation and pixel count. Send the dimensions to Resizer only when they describe actual pixels.

A ratio is a shape, not a resolution

2400 × 1600 and 600 × 400 both have a 3:2 ratio. They have the same shape but very different pixel counts. A ratio of 16:9 alone does not tell you whether the file is 1920 × 1080 or another size.

For a 1200-pixel-wide 3:2 image, height is 1200 × 2 ÷ 3 = 800 pixels. When a calculation produces a fractional pixel, review the rounded output. Small dimensions can show a larger proportional rounding difference.

Frequently asked questions

Does changing the ratio crop the image?

The calculator does not edit a file. In Resizer, crop removes content, padding adds space and stretch changes proportions.

Can I enter centimetres?

A ratio can use any consistent unit on both axes. Do not send physical dimensions to a pixel field without converting them at a stated PPI.

Is portrait 2:3 the same as landscape 3:2?

They are reciprocal shapes. Keep width first and height second so orientation remains clear.