Measuring your windows

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Measuring for Gecko Panes is easy, but we may be able to do it for you. Contact us if you would like to organise a survey.

Before we start.

You’re in safe hands. Measuring for Gecko Panes is really simple and the vast majority of windows need no preparation before installing them, even if the frames are a bit worn. On top of that, small measurement errors or warping issues aren’t a problem because the sponge surround adjusts to them. However, still try to be as accurate as you can.

Weapon of choice.

When measuring, use a quality tape measure. We strongly recommend the ‘top reader’ measures that we sell. We’ll refund the cost from subsequent orders of over £250, depending on the specific product bought.

If you’re measuring many panes, or ones with sides over 80cm, we recommend a Gatortape or laser measure. Our weapon of choice is a Bosch Professional GLM 40 (or better) as other lasers can be inaccurate. If you want, you can hire or buy one from us, and we’ll refund the cost on subsequent Gecko Pane orders.

Right, are you ready to go?

1. Check your windows

Small panes (sides less than 30cm):

For panes with sides less than 30cm, we need the width and height of the glass pane, measured from the middle of each side across to the opposite side.

Large panes (sides more than 30cm):

For bigger panes, measure the width a quarter of the way from the bottom and top of the pane. Take an average of the two measurements (rounding down to the nearest millimetre if necessary). Do the same with the height (measure from a quarter of the way in from each side). 

Georgian windows

Georgian windows typically have several small panes and thin timber glazing bars in each sash. If they get damp, they can sometimes be poorly sealed, allowing moisture to gather between the Gecko Pane and the glass. See Georgian window precautions in our FAQs for guidance.

2. Step by step.


Give each window pane a title, such as “bedroom one, bottom left” or “Peter Pane”.


Make sure there is 11mm between the glass and frame ‘furniture’ (handles, sash closers). If there isn’t, click here for guidance:

Almost there.

When measuring, do not squeeze the tape holder into the corner of the frame and glass. Instead, note the length of the holder, which is often printed on it, and add it to your calculations as you go. If not, use the tape itself to work it out.


Place the end of the tape against the one side of the frame and pull the measure to the other side. Hold the tape as near to the end as you comfortably can to minimise any creases in the tape.


Note the measurement shown while the tape is still in place – this is important, even if it has a lock, as the tape will often slip.

Don’t look down.

Do the same for the height, placing the measure on the bottom of the frame.


Take each measurement twice or ask someone to check your figures, especially for lengths over 70cm. If unsure, purchase a single Gecko Pane initially to see how well you’re doing.


Input measurements onto our website to start your order.