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How to Measure Shades for Windows

Holly Honeycutt

By Holly Honeycutt
Published August 12, 2025

Are you ready to update the window treatments in your home? Window shades provide privacy and light control and come in a wide assortment of materials, colors and textures to match your home's interior. We'll show you how to measure for shades in a few simple steps.

Tools and Materials

Note

Product costs, availability and item numbers may vary online or by market.

Selecting Window Shades for Your Home

Window shades provide privacy and control the amount of light that floods into a room. Some shades are energy efficient, keeping cool air in during the summer and cold air out during the winter. Shades come in a wide array of textures, colors and patterns to match your home's interior.

Types of Window Shades

  • Cellular shades
  • Natural shades
  • Roman shades
  • Roller shades
  • Custom shades

Ways to Install Window Shades

  • Install inside-mount window shades within the window.
  • Install shades with outside mounts to cover the window frame or attach to the wall.
  • If the window frame is deep enough to attach the mounting brackets inside the window frame, you can choose inside or outside mounting. If not, you’ll need to use an outside mount.
  • For outside mounts, a sturdy wall or trim is needed.
  • Always refer to the instructions that are included with your specific product.

Tip

Even if you think your windows are the same size, it's important to measure each one.

Good to Know

Are you still trying to decide between blinds or shades for your home? Check out our buying guide.

Window Shades

Cellular Shades

Roller Shades

Roman Shades

Custom Shades

Blind & Window Shade Parts

How to Measure for Inside-Mounted Shades

Measure For Inside-Mount Cordless Cellular Shades
See the instructions below to measure for inside-mount cordless cellular shades. If your window depth is less than 1-3/4 inches, proceed with an outside-mount measurement. Watch the video instructions.

Measure For Inside-Mount Cordless Top Down Bottom Up Cellular Shades
See the instructions below to measure for inside-mount cordless top down bottom up cellular shades. If your window depth is less than 2-3/4 inches, proceed with an outside-mount measurement. Watch the video instructions.

Instructions
These instructions can be used for all shade types including roller shades, solar shades, cellular shades and Roman shades.

Step 1: Measure the Width

  • Measure the width inside the window frame at the top, middle, and bottom, to allow for variances in construction.
  • Measure to the nearest 1/8 of an inch. 
  • Use the smallest measurement as the window width to make sure that the shades will clear the sides of the window frame.

Step 2: Measure the Height

  • Measure the height inside the window frame on the left, middle and right to allow for variance in construction.
  • Round the measurements down to the nearest 1/8 of an inch.
  • Use the largest measurement as the window width so the shades cover the entire opening.

Step 3: Measure Diagonally

  • If the two diagonal dimensions differ significantly, it may be necessary to order outside-mounted shades for optimal light control and privacy.
  • Measure the window area exactly.

Step 4: Place the Order

  • Round the measurement down to the closet available size for width.
  • If your exact window height isn't available, round up to the next larger height.

How to Measure for Outside-Mounted Shades

Measure For Outside Mount Cordless Cellular Shades
See the instructions below to measure for outside-mount cordless cellular shades. Watch the video instructions.

Measure For Outside-Mount Cordless Top Down Bottom Up Cellular Shades
See the instructions below to measure for outside-mount cordless top down bottom up cellular shades. Watch the video instructions.

Instructions
These instructions can be used for all shade types including roller shades, solar shades, cellular shades and Roman shades.

Step 1: Measure the Width

  • Measure the overall window, including trim on both sides, to the nearest 1/8 of an inch.
  • Add 1-1/2 inches on each side for better coverage.

Step 2: Measure the Height

  • Measure the height inside to the nearest 1/8 of an inch between the highest and lowest points. 
  • Include window trim, adding 3 inches on the top and 1 inch on the bottom, for better coverage.

Step 3: Place the Order

  • Round the measurement up to the closet available size for width. 
  • If your exact window height isn't available, round up to the next larger height.

Good to Know

If you're also considering blinds for your home, we can show you how to take measurements and install them

Let's Get Started

If you're ready to install window shades in your home, it's important to take measurements correctly for optimal appearance and performance. Shades can be installed two different ways: inside-mount or outside-mount.

Inside-Mount Measurements

  • Measure the height
  • Measure the width
  • Measure diagonally
  • Place your order

Outside-Mount Measurements

  • Measure the width
  • Measure the height
  • Place your order

If you’d prefer to leave measuring and installation to the pros, we can help. Shop for window shades online or at your local Lowe's store.