What Size Frame Do I Need for a 30x40 Picture?

The complete guide

You have found the perfect piece of art, a lovely family portrait or a brilliant vintage poster. You unroll it, lay it flat and measure it. It is exactly 30 x 40cm. Now comes the part that can be stressful: buying the frame.

Search for '30x40 frame' and you are met with confusing options, different internal measurements, and questions about borders, mounts and glass sizes. A simple purchase turns into a sum.

It need not. 30 x 40cm is one of the most popular standard sizes in framing, and the right frame depends only on how you want the picture to look. This guide assumes 30 x 40 centimetres (300 x 400mm). Section 1 explains why that matters.

1. The most important question: centimetres or inches?

Before anything else, check your tape measure. '30 x 40' means two very different things.

• 30 x 40 centimetres. A medium-sized standard print, slightly wider and shorter than a sheet of A3. It is a good size for family portraits, art prints and certificates.
• 30 x 40 inches. Much larger, at roughly 76 x 101cm. This is the size of a British 'quad' film poster, and of large statement artwork.

Order a 30 x 40 inch frame for a 30 x 40 centimetre print and you will receive a very large, very empty frame. Check the units before you go to the checkout.

2. Framing edge to edge, without a mount

The simplest way to frame a picture is edge to edge. The artwork fills the whole of the glazed area, and the frame comes right up to the edge of the print.

The golden rule is that a frame's size is the size of the picture that fits inside it. A 30 x 40cm frame is bigger than 30 x 40cm on the outside, by the width of the moulding, but the space inside is made for 30 x 40cm artwork.

3. Framing with a mount, for the gallery look

In a gallery, photographs and prints are rarely pushed right up against the frame. They are surrounded by a border of thick card, usually white. This is the mount, called a mat in the United States.

A mount does three things for a 30 x 40cm picture:

• It looks better. It draws the eye inwards and makes the picture look more important and more valuable.
• It protects. The card creates an air gap between the artwork and the glazing. If condensation forms inside the glass, it cannot touch the print.
• It deals with the rebate. The edge of the mount goes under the lip of the frame, so you lose only a few millimetres of the image, behind the mount.

What size frame, with a mount?

With a mount, the frame has to be larger than the artwork. For a 30 x 40cm picture, the usual step is up to the next standard size, 40 x 50cm. That gives a well-balanced border of 5cm (2 inches) all round.

When you order from EasyFrame, use our picture mounts designer. Tell it your artwork is 30 x 40cm, and we cut the window a few millimetres smaller than the art, so that it cannot fall through and fits perfectly inside the larger frame.

4. What if your art is 'almost' 30 x 40cm?

Sometimes a picture sold as 30 x 40cm turns out, when you measure it, to be 29.5 x 39.5cm. Or it has a printed white border that you want to hide.

Forcing a slightly odd size into a ready-made frame leaves gaps where the backing board shows.

The answer is a frame made to measure. With our custom picture frames you enter the exact dimensions of your artwork, to the millimetre. We make the frame and cut the glazing to fit, so you never have to put up with a loose fit.

Conclusion

Choosing a frame for a 30 x 40cm picture comes down to the look you want. For a modern, edge-to-edge look, choose a 30 x 40cm frame. For a gallery-style border, step up to a 40 x 50cm frame and add a mount.

Measure carefully, check whether you are working in centimetres or inches, and remember the rebate. Then design your frame on the EasyFrame website. We offer a wide range of frames, and with long experience we can advise on the right one.