For a full home window replacement, we recommend that you seek professional assistance and schedule a proper site measure. However, to get a rough size estimate use the following method.

Technical diagram showing window measurements.

To fully replace existing windows, you’ll need both inside and outside measurements. From the inside, remove the casing and measure the width and height from the outside (edge) of the window frame, 6” from the corners and at the centre. This is your outside measurement of window frame (OSM frame).

From the outside, measure the width (brickmould to brickmould) and height (brickmould to sill) of the outside of the windows, 6” from the corners and at the centre. This is your outside measurement with brickmould (OSM brickmould).

Watch the video How to Measure for a Replacement Window.

FAQ Friday is a weekly feature where we answer Frequently Asked Questions about our products, service or industry. To see other FAQs we’ve answered, visit our FAQ page. If you have a question you don’t see an answer for, just ask in a comment or contact us.


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