How To Measure a Window


You may be planning to hang new drapes, replace an old window, or install a new set of storm windows and you’ve gotten down to measuring so that you can order the perfect size.

Precision is key when ordering new windows so that they fit perfectly and don’t leave some spaces awkwardly visible. The key to measuring a window accurately is to do it at different points within the same plane (width, height, and depth) because they are seldom square.

Another handy tip when measuring windows is to use a folding rule with a slide extension. It is more flexible and accurate compared to the traditional tape measure. Below are 3 key step that will guide you on how to measure a window.

Measure The Width

When measuring the width, your goal is to get three different measurements corresponding to the top, middle and base of the window’s opening. Begin by unfolding the rule so that the folding end touches the frame’s inner surface.

Typically, this should be at the jambs, and not the extensions that hold the window in position. Slide out the rule’s extension so that it touches the opposite edge of the casing’s inner side.

To get the full width, simply add the extension’s measure to the number that reads on the rule’s other end. Assuming you began at the bottom repeat the initial step twice, at the middle, and at the top, and use the smallest measure obtained as the width.

Measure The Length

When measuring the window length, start at the sill and moving upwards to the top where the window opening begins. Usually, the sill should be the surface that’s closest to the inside of the window.

Take three height measurements: one at the furthest right, the second at the center, and the third at the furthest left. The most appropriate height measurement is the smallest of the three obtained.

In case your window is sloped a little, there’s no need to worry. You can simply identify the highest point and measure from there. Typically, this point is the one against your window.

Measure The Depth

Effective measuring of the depth requires you to ignore all pulleys and parting strips. This is because, during replacement or installation of a new window, the technicians will remove them.

You should aim to measure the depth occurring between the two stops extending at the front of the window’s frame. Contrary to how you measured the length and width, you do not need to measure at three different positions. However, ensure that you still obtain the shortest measure for your depth.

When measuring depth, ensure that there is an opening 3 ¼ inches wide between the outside blind stop strip and the inside window trim. This extra space accommodates the depth of the new replacement window.

Other Considerations

In some instances, it may be impossible to open your window while attempting to measure the depth. This should not stop you. You can simply measure the depth on each side and add the two measurements together.

Another important consideration is the symmetry of your window opening. Sometimes it may not be a perfect square or rectangle. You can determine this by measuring from the top right corner to the bottom left corner of your window, on both sides. If the diagonals are not equal, the opening is not a perfect square or rectangle.

In case of such an outcome, simply let your window supplier or manufacturer know of this irregularity by informing them that the opening is racked and send them the corresponding measurements.

If you are still having issues with finding the measurements, please contact us and we help make sure you get the exact measurements for your window order.

Have a question? Contact our team to discuss your requirements.
Contact Us