✂️ Photo Print Crop Size Calculator
Enter your original photo's dimensions and your target print size to see the largest possible crop that matches the target's aspect ratio without stretching.
The largest rectangle of the right shape
r = target width / target height
wider than r : crop = (height x r) x height
taller than r: crop = width x (width / r)Only the shape of the target matters, not its size - 4 x 6 and 8 x 12 behave identically at 0.667. Take a portrait 4 x 6 print to a 5 x 7 frame: r is 0.714, the photo is taller, so the crop is 4.00 x 5.60 and 0.4 in of height goes. The defaults lose more - a landscape 6 x 4 cropped to portrait 4 x 6 comes back 2.67 x 4.00.
What the number does not cover
- It never enlarges. The crop sits inside the original, so both figures come back equal to or smaller than what you typed.
- Position is yours. The arithmetic gives the size of the window, not where it goes. A centred crop is the usual reason someone's head ends up against the top edge.
- Resolution shrinks with the crop. Printing wants about 300 pixels per inch, so a 4 x 6 needs 1200 x 1800 px - and cropping a 6 x 4 down to 2.67 in wide throws away more than half the file's width.
Frequently asked questions
Why does my 4 x 6 photo not fit a 5 x 7 frame?
They are different shapes: 4 x 6 is a 3:2 rectangle and 5 x 7 is not. The largest 5 x 7 crop from a 4 x 6 measures 4.00 x 5.60 in, so a strip has to go.
How many pixels do I need for a 4 x 6 print?
1200 x 1800 at 300 dpi, or 800 x 1200 at a still-acceptable 200 dpi. Crop first, then check the pixel count of what is left, because the crop is what gets printed.
What is the crop from a square photo to 4 x 6?
A tall slice: a 6 x 6 photo returns 4.00 x 6.00, keeping the full height and losing a third of the width. Square originals suit 5 x 5 prints better.