Aspect Ratio Calculator
Reduce any width/height pair to its simplest ratio, and see exactly how much of a photo needs cropping to fit a target print size without stretching it.
Ratio & Crop
The crop is centered and maximizes the used area — only the dimension that overshoots the target ratio gets trimmed, the other stays full size.
Why aspect ratio trips up so many prints
A digital photo's aspect ratio is set the moment it's captured, but standard print and frame sizes follow their own conventions — and the two rarely line up. Printing without accounting for the mismatch either stretches the image out of proportion or leaves it letterboxed with unwanted white space, neither of which looks intentional once it's framed on a wall.
Checking the crop before you order prints means you know exactly what will be trimmed off — and can recompose or choose a different print size if the crop would cut through something important, like a face at the edge of the frame.
Frequently Asked Questions
How is the simplified ratio calculated?
The width and height are reduced by their greatest common divisor, the same way you'd simplify a fraction — an 8×10 print reduces to 4:5, and a 4000×3000 pixel photo reduces to 4:3. The simplified ratio is what you compare against a target print size's own ratio to see whether they match.
Why doesn't my photo's ratio match standard print sizes?
Most cameras and phones shoot at 3:2 or 4:3, but common print and frame sizes are 4:5 (8×10), 2:3 (4×6), or 5:7 — different ratios entirely. That mismatch is exactly why a crop is usually needed before printing: without one, the print would either have to distort the image (never a good idea) or leave unprinted margins.
How does the crop calculation avoid distorting the image?
It keeps one full dimension of the source photo untouched and trims only the other, in whatever amount makes the remaining rectangle match the target ratio exactly. A 4:3 photo cropped to a 4:5 (8×10) print keeps the full height and trims width off the sides; a tall photo cropped to a wide target keeps full width and trims off the top and bottom. Nothing is ever stretched.
What if I don't want to lose any of the image to cropping?
Print at a size that matches your photo's native ratio instead of forcing it into a standard frame size — a lab can usually print custom dimensions, and some frames are sold in matching non-standard sizes too. The alternative is adding a mat with extra space on two sides instead of cropping, though that changes the visual composition rather than preserving it.
Does it matter whether I enter pixels or a physical size?
No — the ratio math is the same regardless of unit, as long as the width and height you enter are in the same unit as each other. Use pixel dimensions straight from your camera or phone, or a physical size in inches or centimetres if that's what you have.
Educational estimate based on the numbers you enter — always preview the actual crop in your photo editor or print lab's tool before ordering, since composition (not just math) matters for the final look.