Free tool

Photo Aspect Ratio Calculator

Enter your photo dimensions, choose a print shape, and see the exact crop before you order or export — edge pixels, percentage removed, safe area, and proportional resize.

Instant · dimensions only · no upload

Calculate your photo ratio and crop

1. Enter your photo dimensions
2. Choose the print or canvas ratio
3. Proportional output width (optional)

We calculate the matching height at the selected ratio so the output does not stretch.

Your crop plan

Your photo is 3:4 portrait. The selected print is 2:3 portrait.

Crop about 168 px from each side. That removes 11.1% of the original width and keeps 2,688 × 4,032 px.

Proportional output: 1,200 px wide × 1,800 px high at 2:3.

Source 3:4 → target 2:3

Cropping removes edge pixels; resizing changes pixel dimensions. Neither should stretch the image.

Common photo and print ratios

RatioCommon sizesUsually used for
2:38×12, 12×18, 16×24, 20×30, 24×36Portrait canvases and full-length prints
4:58×10, 16×20Classic framed portraits and close crops
3:46×8, 9×12, 18×24Phone photos, compact cameras and posters
5:75×7, 10×14Small framed gifts and desk portraits
1:18×8, 12×12, 20×20Square frames, grids and profile images
16:91280×720, 1920×1080Screens, slides and wide digital displays

Only the dimensions you type are used, and only in this browser. No photo, filename or account is requested; entered dimensions are not saved or sent in analytics.

Explore portraits for your finished crop →

Why a photo fits one print size but gets cropped in another

Aspect ratio is the shape of an image, not its resolution. A 3024×4032 phone photo simplifies to 3:4; a 12×18 canvas is 2:3. Both are portrait-shaped, but they are not the same rectangle, so a full-bleed print must either trim the longer edges or add empty borders. This calculator shows the trim in pixels and as a percentage before a face, ear, hand or bouquet gets clipped at checkout.

The shaded preview is mathematical, not an uploaded image. Enter the width and height shown in your photo’s info panel, choose the print or frame ratio, and the outlined safe area shows what a centered crop keeps. If the subject is off-center, use the same pixel total but move the crop window toward the subject in your editor instead of cutting equally from both sides.

Crop, resize and print size are three different decisions

Cropping changes composition by removing edge pixels. Proportional resizing changes pixel dimensions while keeping the selected shape. Print quality is a third calculation — pixels divided by physical inches. This tool owns the first two; once the framing is right, the canvas size calculator checks the remaining pixels against real print DPI, and the portrait size guide shows whether that physical size fits your wall.

PortraitGift canvases use a 2:3 artwork area, so 8×12, 12×18, 16×24, 20×30 and 24×36 all share the same crop. Common frames do not: 8×10 and 16×20 are 4:5, 5×7 is its own shape, and 18×24 is 3:4. Choosing the ratio first means every later size in that family keeps the same composition.

How it works

  1. Enter the photo’s pixel width and height from its file information — no photo or filename is requested.
  2. Choose the intended canvas, print or frame ratio, or enter a custom ratio.
  3. Read the centered-crop plan and safe-area diagram; optionally enter an output width to calculate the matching height without stretching.

Frequently asked questions

How do I calculate a photo’s aspect ratio?

Divide width and height by their greatest common divisor. A 3024×4032 photo divides by 1008 to become 3:4; 4000×3000 becomes 4:3. This calculator performs that reduction and labels the orientation automatically.

What aspect ratio is a 12×18 or 24×36 canvas?

Both are 2:3. The same is true for 8×12, 16×24 and 20×30, so one 2:3 crop works across that entire canvas-size family. Turn the canvas sideways and the ratio becomes 3:2.

Why does an 8×10 print crop my phone photo?

An 8×10 print is 4:5, while many phone photos are 3:4 or 4:3. A full-bleed printer has to remove part of the longer dimension to make those rectangles match. The result above gives the exact centered crop; you can shift that crop in an editor to protect an off-center subject.

Does changing aspect ratio reduce photo quality?

Cropping reduces the number of pixels available because edge pixels are discarded; the ratio itself does not blur anything. Enlarging after the crop can reduce effective DPI. Use the canvas size calculator after this tool to rate the cropped pixel dimensions at each print size.

Does this calculator upload or inspect my photo?

No. It accepts width and height numbers only, performs the ratio and crop arithmetic in your browser, and never requests a photo, filename or account. The entered dimensions are not saved or included in analytics.

Explore custom portraits made for a 2:3 canvas →

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