Measuring Windows for Blinds… an Easy Guide

Mistakes in measuring windows for blinds will be greatly reduce if you make it a habit to always follow a few basic steps.

  • Use a 1″ wide, 25 foot steel retractable tape
  • Measure in inches (to the nearest 1/8″) from left to right
  • Always measure width first, then length.
  • Measure each window separately.
  • Measure each window horizontally in three places (top, center & bottom). Record the smallest measurement.
  • Measure each window in two places vertically (2″ from left & right edges. Record the smallest measurement.

There are two ways to mount blinds – inside mount or outside mount. Inside mounted blinds are installed inside the window casing (bet you guessed that!). The minimum depth required will depend on the product you’re installing and the headrail. Information on measuring windows for a specific type of blind is usually included on a manufacturer’s website or in the product and installation guide. Outside mount blinds will mount on the casing, covering more area than the actual glass portion of the window. Simply decide how much of the casing you want to cover. If the casing isn’t flat, it will depend on where you can mount the bracket.

It is a fact of life that regardless of the age of a house or quality of the construction, windows are seldom square and will vary slightly in measurements. That is why, if you are measuring windows for inside mounted blinds, it is critical to measure in 3 places…and record the smallest measurement. If you were installing wood blinds and used the widest measurement, your blind would lower to were the window frame narrowed…and stop! It can be difficult to return a custom order blind because you made a measuring mistake. So remember what my father-in-law always says, “Measure twice, cut once”. Okay, in this case you’re not doing the cutting, but you get the idea. A little extra time spent in measuring the windows will save a lot of hassle down the line.

Measuring windows for blinds isn’t difficult. If you are measuring for a number of windows it just takes a little time and patience. Be sure to number each room and window measurement if you have multiple window sizes.

The guide below is for measuring inside mounted blinds.