Picture Frame Size Chart: Standard Photo & Frame Sizes

Standard photo print sizes

Photo prints come in eight standard sizes, from the 4 × 6 in postcard to the 24 × 36 in poster. The table below gives each one in inches, centimetres, and millimetres, with its aspect ratio and the frame it fits. All conversions use 1 inch = 25.4 mm exactly, so a 4 × 6 in print is 101.6 × 152.4 mm, shown as 10.2 × 15.2 cm. The aspect ratio is the width-to-height proportion: a 4 × 6 in print is 3:2, a 5 × 7 in print is 7:5, and an 8 × 10 in print is 5:4. Prints with the same aspect ratio enlarge cleanly — a 4 × 6 in photo (3:2) crops to 24 × 36 in (3:2) without cutting anything off, but it will not fill an 8 × 10 in frame (5:4) without cropping or a mat.

Standard sizes — printable reference

The mat rule: why the frame is one step up

A frame that matches the print exactly leaves no border, so most framed photos use a mat — a cardboard border between the print and the frame — and the frame is one standard size up. This page suggests the smallest standard frame that leaves at least a 1.5-inch mat border on every side. An 8 × 10 in print fits an 11 × 14 in frame: the mat is (11 − 8) ÷ 2, or 1.5 in, on the sides and (14 − 10) ÷ 2, or 2 in, top and bottom. A 5 × 7 in print fits an 8 × 10 in frame with a 1.5 in mat on every side. A 16 × 20 in print fits a 20 × 24 in frame with a 2 in mat on every side. A 24 × 36 in print needs a custom frame, because no standard frame leaves a 1.5-inch mat around it. If you want no mat at all, buy a frame the same size as the print — the glass holds the print flat, and the frame's own border is the only edge you see.

A4 and other metric prints

Metric paper sizes do not match US photo sizes, so an A4 print (210 × 297 mm) needs a custom lookup: 210 ÷ 25.4 is 8.27 in and 297 ÷ 25.4 is 11.69 in, so the print is 8.27 × 11.69 in with an aspect ratio of 1:1.414 — the square root of 2, which is what makes A-series paper scale so neatly. It fits a 12 × 16 in frame with a mat: the mat is (12 − 8.27) ÷ 2, or about 1.9 in, on the sides and (16 − 11.69) ÷ 2, or about 2.2 in, top and bottom. Enter 8.27 and 11.69 in the custom fields to see it worked out. The same rule applies to any metric print: divide millimetres by 25.4 to get inches, then find the smallest frame that leaves a 1.5-inch mat on every side.

Output · formula · meaning

Who uses this

• The home framer: has an 8 × 10 in portrait and learns it is 20.3 × 25.4 cm, aspect 5:4, and fits an 11 × 14 in frame with a 1.5-inch mat — no measuring, no guessing at the store.
• The gallery-wall builder: is mixing 5 × 7 in, 8 × 10 in, and 16 × 20 in prints and learns they fit 8 × 10 in, 11 × 14 in, and 20 × 24 in frames, so every frame on the wall has the same mat width.
• The A4 printer: prints a photo on A4 paper and learns it is 8.27 × 11.69 in, aspect 1:1.414, and fits a 12 × 16 in frame — a US photo frame will not fit it without cropping.
• The poster buyer: orders a 24 × 36 in poster and learns it is 61.0 × 91.4 cm, aspect 3:2, and needs a custom frame — no standard frame leaves a proper mat around it.

Accuracy & limitations

The conversions are exact: 1 inch is 25.4 mm by definition, so centimetres and millimetres are computed, not estimated, and shown to one decimal place. Standard print sizes are nominal — a lab's 8 × 10 in print can measure a fraction of an inch off, and a home printer's borderless print can be a hair short, so measure a print that must fit a tight frame before ordering. The frame suggestions assume a mat with at least a 1.5-inch border on every side; a frameless clip frame or a frame with no mat takes a frame the same size as the print. Aspect ratios are the reduced width-to-height proportions of the nominal sizes, and a print cropped from a different aspect ratio — a phone photo is usually 4:3 or 16:9 — will not fill a 5:4 frame without cropping or white space. Metric A-series sizes are given for A4 only; other A sizes follow the same rule, dividing millimetres by 25.4.