Image Aspect Ratio Crop Calculator

When the source already matches the target ratio

A 1920x1080 source image cropped to a 16:9 preset needs no cropping at all -- the crop box comes back as the full 1920 x 1080, with a center offset of (0, 0), because 1920:1080 already simplifies to exactly 16:9 (1920/1080 = 1.7778, matching 16/9 = 1.7778 precisely).

This tool calculates the largest possible crop box matching the target aspect ratio that fits within the source image's dimensions -- when source and target ratios already match exactly (as here), that box is simply the entire image, with nothing trimmed away.

Center offset (0, 0) means the crop box is centered on the image with zero pixels trimmed from any edge -- for a source that doesn't already match the target ratio, the offset would show how many pixels get cropped from each side to center the resulting box within the original image.

What this preset calculator does, and its stated scope

Box size only. Different from Aspect Ratio Calculator and Image Crop Ratio Calculator slugs. This tool calculates the crop box dimensions and centering offset for a chosen preset ratio -- it doesn't actually perform the crop on an image file, since that requires image-processing software or a canvas-based tool rather than a pure dimension calculator.

This is deliberately a distinct, more specific tool from a general aspect ratio calculator or a manual crop-ratio calculator -- this one specifically works from preset ratio options (like 16:9, 1:1, 4:5) matched against your source dimensions, rather than requiring you to specify an arbitrary custom ratio by hand.

If your source image doesn't match the preset ratio, the calculated crop box necessarily trims from either the width or the height (whichever is proportionally larger relative to the target ratio) -- centering the crop means losing equal amounts from both opposite edges of whichever dimension gets trimmed.

Related image-sizing and cropping tools

For a more general, non-preset aspect ratio calculation between two arbitrary dimensions, the Aspect Ratio Calculator is the related but distinct tool.

For a different but related crop-ratio calculation approach, the Image Crop Ratio Calculator covers that separate use case.

Frequently Asked Questions (FAQ)