Photo Print Size Guide

Every standard photo size in one place

Photo prints come in a handful of standard sizes, each with its own shape (aspect ratio). This guide lists them in inches and centimetres alongside the aspect ratio and the minimum megapixels needed to print each one sharply at 300 DPI. Use it to pick a size your image's shape suits, and to check your photo has enough resolution before ordering prints.

Why aspect ratio matters

Camera photos are usually 3:2 (DSLR/mirrorless) or 4:3 (phones). Print sizes have fixed ratios too. A 6x4 is 3:2, a 7x5 is 7:5, an 8x10 is 5:4. If the photo's ratio doesn't match the print, some of the image is cropped. Matching the shape first avoids losing heads, edges, or important detail.

Common sizes and their ratios

• 6x4 in (15x10 cm): 3:2, the classic snapshot, matches most cameras.
• 7x5 in (18x13 cm): 7:5, a small crop from 3:2.
• 8x6 in (20x15 cm): 4:3, matches phone photos.
• 10x8 in (25x20 cm): 5:4, a noticeable crop from 3:2.
• A4 / A5: 1:1.41, the print-paper ratio for documents and posters.

How to use this guide

1. Find your photo's aspect ratio (use our aspect ratio calculator if unsure).
2. Pick a print size with a matching or close ratio to minimise cropping.
3. Check your image's megapixels meet the listed minimum for a sharp 300 DPI print.
4. Order or print at that size with confidence.

Notes and limitations

• Minimum megapixels assume 300 DPI; posters viewed from a distance look fine at lower resolution and need fewer megapixels.
• Centimetre sizes are rounded to the nearest common label (15x10 cm is sold as 6x4 in).
• If your photo's ratio doesn't match, expect a crop. Preview it before printing to keep the important parts in frame.

The ratios behind the sizes

Photo sizes cluster into a few aspect ratios, and knowing which is which explains most cropping surprises.

• 3:2 — 6×4, 9×6, 12×8 inches. Matches most DSLR and mirrorless sensors, so these print with no crop.
• 5:4 — 10×8, 20×16. Noticeably squarer; a 3:2 original loses a strip.
• 7:5 — 7×5, 14×10. Between the two.
• 4:3 — many phone photos and compact cameras, and the A-series is close to 1.41:1.
• 1:1 — square, which crops every rectangular original.

The practical rule: match the print ratio to the camera ratio wherever you can, and where you cannot, crop it yourself rather than letting the lab decide.

Metric and imperial do not line up

Photo sizes are imperial by convention almost everywhere, even in metric countries, which produces some awkward near-matches.

A 6×4 inch print is 152×102mm. A5 is 148×210mm — similar in one dimension and very different in the other, so a 6×4 print does not fit an A5 frame or sleeve properly.

Metric sizes sometimes quoted as equivalents (10×15cm, 13×18cm) are close to 6×4 and 7×5 but not identical, so a frame bought for one may show a white edge or crop the other.

When ordering frames, mats or albums, check the actual millimetres rather than trusting that a name matches. A few millimetres is the difference between a print that sits properly and one that does not.

Framing, mounting and the bit that gets hidden

A frame covers the outer edge of a print — typically 3–5mm all round under the rebate. Anything important that close to the edge disappears.

A mount (mat) covers considerably more, and its aperture is usually cut a few millimetres smaller than the print so the print cannot slip through. Standard mount apertures assume standard print sizes, which is another reason to print to a named size rather than a custom one.

Two practical consequences. Leave breathing room around the subject rather than composing to the exact edge. And if a print is going into a specific frame, measure the aperture first — frames sold as "10×8" sometimes mean the outer dimension, not the image area.

Paper finish, and how long prints last

Finish affects appearance and handling more than most people expect.

• Gloss — strongest colour and contrast, and shows every fingerprint and reflection. Poor behind glass.
• Matte — no reflections, slightly flatter colour, and much better for framed work and for prints that will be handled.
• Satin / lustre — the compromise most labs default to, and usually the safest choice.

On longevity: prints fade with light exposure, and how fast depends on the ink, the paper and where it hangs. Direct sunlight is the main enemy, and pigment inks generally outlast dye inks. For anything you care about, keep the digital file — it is the only copy that does not fade, and it costs nothing to reprint.