Aspect Ratio Crop Calculator
Work out crop dimensions to fit an image to a target aspect ratio.
Fitting an image to a shape
Cropping an image to a specific aspect ratio — 16:9 for video, 1:1 for a square, 4:5 for a portrait post — means working out the exact pixel dimensions that hold that ratio within your image. This calculates those dimensions from your image size and target ratio, so you crop to the right shape precisely rather than by eye.
Enter the image size and target ratio, and the crop dimensions are calculated.
Ratio, resolution and where to crop
Two things the numbers help with. First, the largest crop of a given ratio that fits inside your image — cropping to a ratio always means losing some pixels from one dimension, and the calculation tells you exactly how much and what final size you get. Second, planning: knowing the resulting dimensions upfront tells you whether the crop will still be large enough for its purpose, or whether the source is too small. Where within the image to place the crop is a creative choice, but the dimensions that make the ratio exact are pure arithmetic, done here.
Aspect Ratio Crop Calculator FAQ
What does it calculate?
The pixel dimensions of the largest crop at your target aspect ratio that fits within your image.
Why does cropping to a ratio lose pixels?
Because the image's current ratio rarely matches the target, so one dimension must be trimmed to fit the new shape.
Is anything uploaded?
No. The calculation happens in your browser.