Most framing mistakes happen before a frame is ever made. A picture that's a centimetre too big for its frame won't go in. One that's a centimetre too small slips about behind the glass. And a frame sized to the wrong measurement, such as measuring the outside instead of the inside, is a very expensive way to learn the difference.
This guide covers the standard frame sizes used in the UK, what the measurements on a frame actually refer to, and how to measure your own piece so a made-to-measure frame fits first time.
Standard picture frame sizes in the UK
UK framing uses three systems side by side: imperial photo sizes, metric A sizes for paper, and metric poster sizes. A frame is always named by the size of the picture it holds, not by its outside dimensions.
Photo and print sizes
| Size (inches) | Size (cm, approx.) | Typically used for |
|---|---|---|
| 6 × 4 | 15.2 × 10.2 | Standard photo prints |
| 7 × 5 | 17.8 × 12.7 | Larger photos, postcards |
| 8 × 6 | 20.3 × 15.2 | Small prints |
| 10 × 8 | 25.4 × 20.3 | Portrait photography, small art prints |
| 12 × 10 | 30.5 × 25.4 | Art prints, certificates in a mount |
| 14 × 11 | 35.6 × 27.9 | Art prints |
| 16 × 12 | 40.6 × 30.5 | Medium prints and paintings |
| 20 × 16 | 50.8 × 40.6 | Medium to large prints |
| 24 × 20 | 61.0 × 50.8 | Large prints and paintings |
| 30 × 20 | 76.2 × 50.8 | Panoramic and large prints |
| 40 × 30 | 101.6 × 76.2 | Statement pieces |
A sizes
| Size | Millimetres | Inches (approx.) |
|---|---|---|
| A5 | 148 × 210 | 5.8 × 8.3 |
| A4 | 210 × 297 | 8.3 × 11.7 |
| A3 | 297 × 420 | 11.7 × 16.5 |
| A2 | 420 × 594 | 16.5 × 23.4 |
| A1 | 594 × 841 | 23.4 × 33.1 |
| A0 | 841 × 1189 | 33.1 × 46.8 |
Poster sizes
Common poster frames in the UK are 30 × 40 cm, 40 × 50 cm, 50 × 70 cm and 61 × 91 cm (the last is the metric version of the 24 × 36 inch poster).
One thing to watch: A sizes and imperial sizes are close but never identical. An A4 print will not sit properly in a 12 × 10 inch frame, and an A3 print is noticeably narrower than a 16 × 12 inch opening. Measure the actual print, not the size printed on the packaging.
The three measurements on a frame
This is where most confusion comes from. Every frame has three sizes, and they are not interchangeable.
The rebate size. Turn a frame over and you'll see a recessed step running around the inside edge. That's the rebate, and it's where the glass, mount, picture and backing sit. When a frame is described as "20 × 24 inches", this is almost always the measurement being given. It is the one that matters most.
The sight size. From the front, the frame's inner lip overlaps the edge of the picture slightly. The sight size is the area you can actually see. It's a little smaller than the rebate, typically by a few millimetres on each side, which means the very edge of your picture will be hidden.
The outside size. The full width and height of the frame, moulding included. This is what you need for planning a wall, but it's no use for ordering. As a rough guide, the outside size is the picture size plus twice the width of the moulding — a 16 × 20 inch picture in a 3 inch moulding will be roughly 22 × 26 inches overall, and a touch less in practice because the lip overlaps the picture.
How to measure your picture for a made-to-measure frame
1. Measure the piece itself
Lay the picture flat and measure the width, then the height, with a metal tape rather than a cloth one. Measure across the top and the bottom, and down both sides. Old prints and hand-stretched canvases are rarely perfectly square, and if the two measurements differ, use the larger one.
Always write the measurements down as width × height, and say which is which. A 16 × 20 frame and a 20 × 16 frame are the same shape turned on its side, and it's an easy thing to get backwards.
2. Decide what's going in the frame
What you measure depends on what the frame needs to hold.
- A print or photograph with a mount: measure the outer edge of the mount, not the picture. A mount (the card border around a picture) usually adds 5–8 cm on each side, and more for small works that need room to breathe.
- A print without a mount: measure the paper. Remember that a few millimetres of it will disappear behind the lip, so avoid framing tight to a signature or an important edge.
- A painting on stretched canvas: measure the canvas edge to edge. Check its depth as well. Many modern canvases are 3–4 cm deep, and older frames were often made with shallower rebates intended for panels and thinner stretchers. If your canvas is deep, tell us before we make the frame.
- A mirror: measure the glass, and let us know its thickness.
3. Allow a little tolerance
A picture should sit in its rebate without being forced. Framers usually build in a couple of millimetres of clearance. If you're sending us exact dimensions, give us the true size of the piece and we'll allow for it; don't add your own extra on top.
4. Choose your moulding width
The width of the moulding changes the character of a frame more than almost anything else. As a general principle, larger pictures carry wider mouldings well, and small works can look swamped by a very deep frame, though an oversized frame around a small piece can be a wonderful deliberate choice.
Our made-to-measure mouldings range from a delicate ¾ inch to a substantial 4 inches.
How our made-to-measure sizes work
Every one of our made-to-measure frames is handmade to order in the UK and offered in four size bands:
| Band | Holds a picture up to |
|---|---|
| Small | 10 × 12 inches |
| Medium | 16 × 20 inches |
| Large | 20 × 30 inches |
| X Large | 30 × 40 inches |
Pick the band your picture fits within, then send us your exact dimensions and we'll build to them. If your piece is larger than 30 × 40 inches, or is an unusual shape, get in touch and we'll quote for a bespoke frame.
A word of caution: because made-to-measure frames are made to the figures you give us, we can't take them back if the measurements turn out to be wrong. If you're unsure which measurement we need, send us a photograph of the piece with a tape measure against it and we'll check it for you before anything is made.
Planning a wall, not just a frame
Once you know the outside sizes of your frames, you can plan the wall. Cut paper templates to each outside size, tape them up, and live with the arrangement for a day before you drill a single hole. We've written more about this in our guide to gallery wall ideas using vintage and ornate gold frames.
If you'd rather hand the whole thing over, our Frame Curation Service takes your wall's measurements and photographs, and comes back with a selection of frames and two to three layout plans drawn to size.
Quick reference
- A frame's stated size is the picture size, not the outside.
- Measure width first, then height, and say which is which.
- Measure all four sides and use the largest figure.
- For a mounted picture, measure the mount.
- For a canvas, check the depth.
- Unsure? Send us a photo with a tape measure in shot before you order.
Browse our made-to-measure frames or our ornate vintage frames, which come in fixed sizes listed on each piece.