Window Renovation: How to Measure for a Replacement Window

Any window renovation project begins first and foremost with a simple and efficient measurement session, before even visiting your local window retailer or supplier.

This very crucial step is surprisingly quick! All it takes is a little knowledge of the window “language”.  In order to take measurements for your replacement window, you will need a measuring tape and something to record your measures (pen and paper or a smart phone, for example).

Below are instructions on how to measure for a window renovation project, where you replace an existing window by a new one. The measuring process differs for new construction projects.

How to Measure

First, remove the interior casing or trims around the window to completely reveal the existing window frame. Take this opportunity to check the condition of your frame.

Note that you will have to take measurements inside as well as outside of your home.

Using your measuring tape, measure:

  1. The interior width of the window (from the outer edges of the existing window frame)
  2. The interior height of the window (from the outer edges of the existing window frame)
  3. The exterior width (from one edge of the exterior cladding to the other, for example, vinyl to vinyl or brick to brick)
  4. The exterior height (again, vinyl to vinyl or brick to brick, for example)
  5. The depth: the distance between the drywall on the inside and the outer edge of the frame
  6. The height of the sill: the distance between the bottom of the window and the floor, to determine, for example, the height of the handle


For every dimension, measure the opening in three different places. If you obtain varying measurements, always write down the smallest, or narrowest, one.

You may now proceed to your local window retailer or supplier to shop for your window model, colour, and various options (double vs. triple glazing, etc.).

If In Doubt… Call On the Professionals!

For any window renovation project, never hesitate to call on a professional and experienced design and installation team! Windows can represent a large investment and every order is custom-made. There is no room for error!

Canadian leader in the door and window industry and particularly known for its unique premium door designs, Portatec benefits from a highly-experienced sales team as well as a meticulous and proficient installation team. Do not hesitate to contact Portatec to get a quote!

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