Aspect ratio toolkit

Free aspect ratio tools

Work out a ratio, convert megapixels and dimensions, or preview how a frame changes when it is cropped or padded.

Aspect Ratio Calculator

Enter any width and height to simplify the ratio and see its decimal value.

Compare a no-crop canvas with a centered crop for a different target ratio.

Find the crop size, removed pixels, retained area and lost percentage for a target ratio.

Turn MP and aspect ratio into pixel dimensions, or find the exact MP count of a resolution.

Find the active image size and exact bars required to fit one ratio inside another.

Calculate PAR, sample SAR, display aspect ratio and square-pixel export dimensions.

Compare 16:9, 9:16, 1:1, 4:5, 4:3 and 21:9 with common pixel dimensions.

Use the calculator to reduce dimensions such as 1920×1080 to 16:9.

Use the megapixel calculator to estimate both pixel dimensions.

Use the aspect ratio calculator to solve the missing dimension. To change the shape instead, compare canvas and crop options with the converter.

Use crop loss to measure what will be removed before you edit.

Write down the original dimensions, the required output and whether cropping is allowed. Then choose the operation, not just a ratio name.

Same shape, smaller size: use the missing-dimension walkthrough, then resize with proportions locked.
Different shape, edges may be removed: use the crop walkthrough, position the crop and resize afterward.
Different shape, all content must stay: calculate a fit inside the fixed output frame, then add padding or a background in the editor.
Only a target ratio is known: compare an expanded canvas and a centered crop with the converter before choosing final pixels.

Reopen the exported copy in the image checker to confirm its dimensions. A calculation plans the edit; it does not modify the source file.