Measuring your windows is something you can do without any prep. It’s pretty easy once you know exactly what you need to measure, though it is a little more work than simply running a tape measure along with your window frame. If you shop at Budget Blinds of North Glendale, you won’t have to worry about any of this — our co-owner James will personally come out and measure your windows to guarantee the perfect fit.

However, if you want to be prepared for your consultation or are doing it yourself, we created a guide for how to measure a window for blinds.

Measuring For Inside Window Mounts

An interior mount is one that is fitted inside the window frame. These are the common standard for most window coverings, including blinds and shades, and some shutters. There are a few things you should remember when you’re looking to add interior mounts to your window.

Firstly, no deductions! You’ll want to take exact measurements and write them down somewhere (you’ll likely forget otherwise, since there are a few numbers you’ll need). Your design specialist or window treatment supplier will know if any deductions will need to be made based on the product.

Second, make sure you’re using a flexible measuring tape so you can get it flush against the frame. This helps ensure accuracy. Those metal tape measures that bend against corners are fine to use, as long as you can make it as flush against the window as possible.

Finally, double-check all of the mounting requirements to ensure that your window is deep enough to accommodate an interior mount. If it’s too shallow, you’ll need to choose an outside mount or switch to another product.

How to Measure for an Interior Mount

To get an accurate measurement for your interior mount, follow these steps:

Put your measuring tape in the top left corner and drag it flush with the top right corner. Markdown the measurements.
Go halfway down the window and measure from the middle of the frame to the opposite end. Markdown the measurements.
Finally, measure the bottom left corner to the bottom right corner. Markdown the measurements.
Compare the three measurements you made above. The narrowest of the three will be the size you’re going to need.
Measure the height of your window following the same format (measure the right side, the height at the center, and the height at the left side of the frame).

Make sure your measuring tape is flush with the sill and the top of your window frame. Mark each measurement down and compare them. Take the longest of the three measurements.
If you prefer to keep the blind from resting on the sill, deduct a 1/4" from the height.
If your window does not have a sill, measure to the point you would like the blind to reach.

Finally, measure the window’s diagonal on both sides. Start on the top left and measure down to the bottom right corner. Markdown the measurement.

Repeat and compare
If the two diagonal dimensions differ significantly, it may be necessary to order an outside mount for optimal light control and privacy.

How to Measure For Outside Mounts

Outside mounts are ones that are outside of your window frame. They hand outside your window frame to add depth for things like curtains, drapes, shutters, and more. Measuring these is a little more difficult, though it does require less measurements. These are rare for window blinds, but not unheard of!

Here’s how you do it.

Measure the distance from the outermost points you would like the blind to cover.

To minimize light leakage the blind should overlap the window opening by at least 1 1/2" on each side for a total of 3" on the entire width.

Measure distance from where the top of the blind will be located to the window sill.

The blind should overlap the window opening on the top by at least 1-1/2". Some products may require more than 1-1/2" above the window for mounting hardware.

How to Measure for Vertical Window Blinds

Vertical window blinds aren’t the same as horizontal blinds and measuring for them is going to look a little different too.

Inside Mount For Vertical Blinds

Measure the width inside the window opening at the top, and round down to the nearest 1/8" measurement.
Measure the height inside the window opening from the top of the window opening to the window sill three times.

Measure once on the left, at the center, and on the right and take the shortest of the three measurements, and round down to the nearest 1/8" measurement.

Outside Mount For Vertical Blinds

Measure the distance from the outermost points you would like the blind to cover.

To minimize light leakage and ensure privacy the blind should overlap the window opening by 4" on each side for a total of 8" on the entire width.

Measure the distance from where the top of the blind will be located to the window sill.

The blind should overlap the window opening on the top and the bottom by at least 3".

If the blind will hang to the floor, take a 1/2" deduction on the height to allow for operating clearance.

Measuring Vertical Blinds for Patio Doors

If you’re trying to measure for patio doors inside of windows, then we’ve got you covered too. You’ll likely need someone else to assist you with these, just to make holding the tape measure a little easier.

Measure the distance from the outermost points you would like the blind to cover.

To minimize light leakage and ensure privacy the blind should overlap the window opening by 4 inches on each side for a total of 8 inches on the entire width.

Consider the size of the vertical blind stack. Allow sufficient overlap for easy access through the door.
Measure distance from where the top of the blind will be located to the floor on the left side, center, and right side of the window.

The blind should overlap the window opening on the top by at least 3".

Take a 1/2" deduction on the height to allow for operating clearance.

Or let the professionals do it for you. At Budget Blinds of North Glendale, we’re passionate about working with you to turn your house into your dream home. From the initial design consultation to professional installation, we’re ready to help you every step of the way. Give us a call to get started.