§ 11 — Tools / 21Photo files● Runs in your browser
Aspect ratio crop tool
Crop a photo to 4:5, 1:1, 16:9 or a custom ratio with rule-of-thirds or golden-ratio guides, then save the crop at full resolution.
All tools- Crop size
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- Offset
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- Original
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How it works
The method behind the numbers.
The crop box always has the exact ratio you pick. It starts as the largest box of that ratio that fits inside the photo; the crop size slider shrinks it from there. The photo is cropped from the original pixels, so the saved file is not resampled.
ratio = width ÷ height
box width = long-side fit × crop size
box height = round(box width ÷ ratio)- Moving the box. Drag it, or focus it and use the arrow keys. Each press moves about 0.2% of the photo's long edge; hold Shift for ten times that.
- Guides. Thirds puts lines at ⅓ and ⅔ across and down. Golden puts them at 0.382 and 0.618, the golden section. They are drawn on the preview only, never on the saved file.
- Whole pixels. Box sizes round to whole pixels, so a ratio can be off by a fraction of a pixel on one side.
- Format. JPEG is saved at quality 92, which is a fresh lossy encode of the crop. Choose PNG to avoid that; the file will be much larger. Transparent areas become white in a JPEG. Camera metadata and colour profile are not carried over.