Choosing a frame should be the easy, enjoyable part of putting something you love on the wall – yet frame sizing trips up more people than almost anything else. Should you buy A4 or 10x8? Is your photo measured in inches or centimetres? And what changes once you add a mount? This complete guide walks you through every standard picture frame size used in the UK, with accurate cm and inch conversions, so you can order with confidence the first time. Everything at FramesPlus is a ready-made, standard-size frame, which means the dimensions below are exactly what you can pop straight onto your shelf or wall.
What “standard” picture frame sizes actually means
In the UK, standard frame sizes fall into two families. The first is the A-series (A1, A2, A3, A4 and so on), which is the paper and poster standard used across Europe. The second is traditional photo sizes measured in inches, such as 6x4 and 10x8, which come from print-lab conventions. Knowing which family your artwork belongs to is the single most useful thing you can do before you buy, because it tells you exactly which frame to reach for.
A-size frame dimensions (A1 to A6)
A-sizes follow a neat rule: each size is exactly half of the one above it. A4 is half of A3, A3 is half of A2, and so on. This makes them brilliant for posters, prints, certificates and children’s artwork. Here are the standard A3, A2 and A1 frame dimensions alongside the smaller sizes, in both centimetres and inches.
| Size | Centimetres (cm) | Inches (in) |
|---|---|---|
| A1 | 59.4 x 84.1 cm | 23.39 x 33.11 in |
| A2 | 42.0 x 59.4 cm | 16.54 x 23.39 in |
| A3 | 29.7 x 42.0 cm | 11.69 x 16.54 in |
| A4 | 21.0 x 29.7 cm | 8.27 x 11.69 in |
| A5 | 14.8 x 21.0 cm | 5.83 x 8.27 in |
| A6 | 10.5 x 14.8 cm | 4.13 x 5.83 in |
So if you have ever wondered about the A4 frame size in cm, it is 21.0 x 29.7 cm – the same as a standard sheet of printer paper. A4 and A3 are far and away our most popular sizes for prints and posters, and you can browse the full spread over on our complete frames collection.
Common photo and print sizes (6x4, 7x5, 8x6, 10x8, 12x10)
If your images came from a photo lab, high-street printer or your phone’s print service, they will almost certainly be in inches. These photo frame sizes are the classics, and every one of them is a standard fit you can order off the shelf.
| Photo size (inches) | Centimetres (cm) | Best for |
|---|---|---|
| 6x4 in | 15.2 x 10.2 cm | Everyday snaps, standard prints |
| 7x5 in | 17.8 x 12.7 cm | Portraits, keepsake photos |
| 8x6 in | 20.3 x 15.2 cm | Family photos, small prints |
| 10x8 in | 25.4 x 20.3 cm | Statement portraits, gifts |
| 12x10 in | 30.5 x 25.4 cm | Larger prints and artwork |
The 6x4 photo is the most common of all – it is the default size most labs print – while 10x8 has become the go-to for framed gifts and mantelpiece portraits. Our classic range covers all of these popular photo sizes in timeless finishes.
Square frame sizes
Square frames have surged in popularity thanks to Instagram and modern photo prints. Common square frame sizes in the UK include 20x20 cm (roughly 8x8 in), 25x25 cm (about 10x10 in) and 30x30 cm (around 12x12 in). They look wonderful in a symmetrical grid on a wall, or grouped in threes on a shelf. If you love a clean, contemporary look, take a browse through our dedicated square frames collection.
How to measure your print (measure the artwork, not the frame)
Here is the golden rule that saves the most returns: always measure the artwork itself, not any frame it might already be in. Frame sizes are named after the picture they hold, not their outer edge, so a “10x8 frame” is built to display a 10x8 inch print.
- Lay your photo, poster or print on a flat surface.
- Measure the width first, then the height, edge to edge of the printed area you want on show.
- Match those numbers to the charts above – if it is close to a standard size, that is the frame you need.
- If you are between sizes, size up rather than down; you can always add a mount to make up the difference.
With a mount vs without a mount
A mount (sometimes called a mount board or mat) is the card border that sits between your picture and the frame. It does two lovely things: it gives your artwork room to breathe and it makes even a small photo feel more considered and gallery-like.
This is where sizing needs a little care. A frame with a mount is described by two measurements – the outer frame size and the smaller aperture (the window the mount cuts out for your picture). For example, an A3 frame with a mount might hold an A4 print, with the mount filling the gap. If you want that framed-in-a-gallery finish, our frames with a mount take the guesswork out of it. For more help pairing print sizes with mounts, our size guide lays it all out.
Frequently asked questions
What size frame do I need for an A4 print?
An A4 print (21.0 x 29.7 cm) needs an A4 frame if you want it edge to edge, or an A3 frame with an A4 mount aperture if you would like a border around it.
Is 10x8 bigger than A4?
They are close but not identical. A4 is 21.0 x 29.7 cm and 10x8 inches is 25.4 x 20.3 cm – A4 is longer and narrower, while 10x8 is a little wider and shorter. Always match your frame to the print you actually have.
Can I put a smaller photo in a bigger frame?
Yes – that is exactly what a mount is for. Choose a larger frame with a mount aperture cut to your photo’s size, and the mount neatly fills the surrounding space.
Are your frames a standard fit?
Absolutely. Every frame we sell is a ready-made, standard UK size, so the dimensions in this guide are exactly what you will receive.
Ready to find the perfect fit? Explore our full range of standard frames – with free UK delivery and 30-day returns, it is easy to get it just right.