How to Measure Inside-Mount Window Blinds

White inside-mount window blinds measured with yellow tape measure closeup

The Spruce / Sarah Lee

Project Overview
  • Working Time: 20 - 36 mins
  • Total Time: 20 - 30 mins
  • Skill Level: Beginner
  • Estimated Cost: $0

Because of their utilitarian function, window dressings are often overlooked for their value in accenting or creating a beautiful home aesthetic. But the fact is that even the simplest window dressings offer a variety of opportunities to play with the small details that can make a nice room into something breathtaking. Window blinds are a great example of a small detail that can have a big impact. With or without draperies, window blinds offer light control and privacy to any room, but they can also be a source of beauty—particularly the "inside mount blind" that has no external mounting and appears to emerge directly from within the window.

Modern blinds offer a variety of colors, patterns and textures can play with these same elements in the rest of your decor allowing you to create a layered and professional look in your spaces. The hardest part: hanging the blinds. And the first step to hanging anything is getting the measurements just right. You'll need the right tools and just a bit of know-how. So before you plunge into your next design masterpiece, take a second to peruse this brief step-by-step guide to measuring for inside mount blinds to make sure you get your measurements right the first time. 

What You'll Need

Equipment / Tools

  • Steel measuring tape
  • A ladder or step stool (if the window is high)


  • Paper and pencil


Materials and tools to measure inside-mount window blinds

The Spruce / Sarah Lee

  1. Determine If an Inside Mount Blind Is the Right Option

    For an "inside mount blind" you must determine if there's enough room to install a blind and its heading in the window opening. If the edge of the window is flush with the wall, you'll need to use an outside mount blind.

    Inside-mount blind fixtures installed in front of bright window

    The Spruce / Sarah Lee

  2. Measure Window Width

    Measure the width of the window opening in 3 places—at the top, in the middle and along the bottom edge or sill. Use the measurement to within 1/8 inch. You'll use the narrowest of these three measurements for your inside-mount blind width.

    Yellow tape measure pulled across window to measure wdith

    The Spruce / Sarah Lee

  3. Measure Window Height

    Measure the height of the window opening in 3 different places—along with the left side, in the middle and along the right side. Use the measurement to within 1/8 inch. You'll use the longest of these measurements for your inside-mount blind length.

    Yellow tape measure pulled from top of window for inside-mount blinds

    The Spruce / Sarah Lee

Tips for Measuring Windows for Blinds

  • Always measure to the nearest 1/8 of an inch. Do not round the measurement up or down.
  • When writing the measurement, list the width first and then the height. The proper measurement would be "width x height."
  • If you are not sure about how to make accurate measurements, you'll want to pay to have someone from the blind company come to your home to measure.
  • If you provide your own measurements, you'll be responsible if the blinds do not fit. Blinds are custom items and must be perfect to look right.