PhotoCalcs
Aspect Ratio Calculator — Convert & Crop
Convert between aspect ratios, work out the crop for a different print or display format, and resize proportionally.
How We Calculate This
Aspect ratio is the proportional relationship between width and height:
Aspect Ratio
Ratio = width ÷ height (simplified using the greatest common divisor)
Cropping to a Target Ratio
If the image is wider than the target ratio, the height is kept and the width trimmed (new width = height × target ratio). If it is taller, the width is kept and the height trimmed (new height = width ÷ target ratio). The pixels removed are split evenly across the two edges.
Proportional Resize
New height = new width ÷ aspect ratio — scales the cropped image to your chosen output width without distortion.
Frequently Asked Questions
3:2 is standard for 35mm film and most DSLR/mirrorless cameras. 4:3 is used by Micro Four Thirds and many phones. 16:9 is widescreen video. 1:1 is square (Instagram). 5:4 is a common print size (8×10 inches). 4:5 is Instagram portrait.
If the print aspect ratio differs from the image, you must crop. For example, a 3:2 image (6000×4000) printed at 5:4 (8×10 inch) requires cropping 1000px from the long side — 500px from each side — leaving 5000×4000px (20MP). Always check the crop before ordering prints.
To crop to a target ratio, keep one dimension and recalculate the other. For 6000×4000 (3:2) to 5:4: the image (1.5) is wider than 5:4 (1.25), so keep the 4000px height and set the new width to 4000 × 5⁄4 = 5000px. That trims 1000px of width — 500px from each side — giving 5000×4000px.
Absolutely. Wider ratios (16:9, 2.35:1) emphasise horizontal landscapes and panoramic views. Square (1:1) creates balanced, symmetrical compositions. Portrait orientations (4:5, 2:3) suit vertical subjects. Choosing the right aspect ratio is a key composition decision.
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Last updated: June 2026
All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.