Frame Designer Measuring Guide

It is important that you measure accurately for your frame. We’ve tried to cover every possibility in the guide below while keeping it simple. Just scroll down to the section that applies to the frame you’re designing.

You can measure and enter your dimensions in cm or mm. If you need to convert from inches to millimetres, multiply by 25.4.

Standard Size Frames

If you’re using our Frame Designer to create a frame based on ‘Standard Sizes’, the apertures and (if applicable) mount borders are all preset for your convenience. You don’t need to enter any measurements. 

For instance, if you chose a standard A4 frame without a mount, we’ll make this so that your A4 piece fits comfortably. If you add a mount, we will allow a suitable border width and cut the aperture a little smaller than A4 to allow your A4 piece to fit behind the aperture (and not fall through!).  

If you want full control over the aperture and all mount border sizes you can switch to ‘Custom Frame Sizes’. 

Measuring for Just a Frame (Custom Sizes)

If you are designing just a frame without any mount, you’ll simply need to give us the outer dimensions of the piece to be framed. We’ll make the frame so that your piece fits comfortably.

Note: If you can’t see where to enter these dimensions in the ‘What Size’ section, you may be set to Standard Sizes. You need to switch to ‘Custom Frame Sizes’ in section 1 to get full control over apertures and border sizes.

So if you want to frame a picture that is 300mm wide by 200mm high, just enter those dimensions in the ‘What Size’ section of the Frame Designer.

It’s that easy!

Even if your image has a printed border that you want to show, or is already mounted, measure to the very edge of the item. Make sure you read the note below so that you’re not caught out by a frequent measuring error.

Note: Every frame has a small ‘lip’ that overlaps the edge of what it mounts. For this reason, if the item you’re measuring is already in a frame, make sure you first remove it from the frame and carefully measure the exact size of the piece. Don’t measure it from the front when it’s in a frame!

Measuring for a Frame AND a Mount (Custom Sizes)

If you are designing a frame and mount, you’ll need to give us two sets of measurements – the aperture size and the mount border sizes.

Note: If you can’t see where to enter these dimensions in the ‘What Size’ section, you may be set to Standard Sizes. You need to switch to ‘Custom Frame Sizes’ in section 1 to get full control over apertures and border sizes.


What aperture size to use:

All you need to tell us is the exact size that you’d like the mount aperture to be. We will cut it precisely to the size you give us. Enter these measurements as the ‘Aperture Width’ and ‘Aperture Height’ in the ‘What Size’ section of our Custom Frame Designer.

Measuring for the aperture:

Your aperture needs to be a little smaller than the image you want to mount so that you can position the picture behind the mount (and so it doesn’t fall through!). We’d suggest allowing at least 2.5mm on each side.

For example, if you want to frame an A4 image (297mm x 210mm) you should make the aperture 292mm x 205mm).

Your picture may have a white or coloured border, some of which you may want to see within the mount aperture.

Again, you simply need to measure carefully and tell us the exact aperture you require. We will cut it precisely to the sizes you give us.


Mount border sizes:

All you need to tell us is the border widths you require. 

The size of the mount border you enter will set the width from the aperture to the outer edge of the mount.

So adding borders of 100mm on all sides will make the overall mount size 200mm wider and 200mm taller than the aperture size you gave us.

Note: Each frame has a small lip that will overlap the edge of the mount (and keep it in place). The lip size varies depending on the frame, but is normally about 5mm, so approximately 5mm of your mount will be hidden under the frame lip on all sides. You may want to allow for this.

A framer’s hint:  Most standard frames with mounts simply have the same size border on the top, bottom and sides, but a professional framer will normally create a slightly deeper bottom border. This prevents the optical illusion of the picture appearing to sit too low in the frame. The slightly deeper bottom border gives more ‘balance’ to the overall piece. Not everyone agrees, but you might want to check it out for yourself. As a guide, making the bottom border 10% greater than the top border is about right.

Double Mounts

You can enhance the look of your mounts by adding a second layer of mount board to make it a double mount. 

Double Mount Widths

The most important thing to note is that adding extra mount layers does not increase the width of the overall mount borders.

The width from the aperture to the outer edge of all mounts is set by the border sizes that you entered – irrespective of how many mount layers you choose.

Entering the ‘Offset’:

If you choose to add a double mount, you just need to tell us the ‘offset’ between each layer.

The offset dimension you enter will be the amount of mountboard showing beneath the upper layer. For instance, if you have a blue top mount and a pale grey second mount, and you set the offset of 7mm, you will see 7mm of pale grey mount showing beneath your blue top mountboard.

Remember, changing the offset does not change the overall width of your mount borders. It just sets how much of the lower mount is shown.


Unit 7 & 8, Courtyard Workshops
Bath Street
Market Harborough
LE16 9EW