How to Measure for Automatic Window Shades | Three-Point Method

Automatic window shades add convenience, but ordering the wrong size means return hassles and wasted time. The same three-point measurement rule applies whether you’re installing manual blinds or motorized shades—windows are rarely perfectly square, and one measurement will miss the narrowest spot. Here’s how to get it right the first time, with the extra checks motorized shades need.

Inside Mount: Measure Width, Height, and Depth

An inside mount places the shade inside the window frame for a built-in look. For automatic shades, you also need to verify the frame is deep enough to hold the motor housing and brackets.

Use a metal tape measure and record every measurement to the nearest 1/8 inch. A cloth tape can stretch and give you a false reading.

• Width: Measure at the top, middle, and bottom of the window opening.
• Height: Measure at the left, center, and right. The rule varies by shade type—check the product’s guide.
• Depth: Measure from the front of the frame to the back at the top center.
• Obstructions: Note any window cranks, locks, or handles that could block the shade cassette. If an obstruction protrudes into the opening, consider an outside mount.

Outside Mount: Coverage and Overlap

Outside mount shades mount above or outside the frame, covering the entire window opening and some surrounding wall. This style works well for shallow frames or windows with obstructions. It also maximizes light blockage and privacy since no light leaks through the gap around an inside-mount shade.

• Width: Measure the full area you want covered, then add at least 1 1/2 inches on each side for overlap.
• Height: Measure from where the top of the shade will sit to where you want the bottom to fall.
• Overlap rule:

Motorized-Specific Checks

Automatic shades add a few extra decisions the standard manual guide doesn’t cover. Before you order, confirm these items:

• Power source location: Is there an outlet or hardwired power near the window? Battery-powered options exist but require periodic battery changes.
• Control side: Decide whether the motor and controls sit on the left or right side of the shade. Record this preference when ordering.
• Clear space above the frame: Motorized brackets and cassettes can push the shade further away from the glass than manual ones.

For a detailed comparison of the top automatic window shades on the market, including power options and installation notes, see our tested automatic window shade roundup.

FAQs

How do I know if my window frame is deep enough for motorized shades?

Measure the inside depth at the top center of the frame. If your frame depth is less, you can switch to an outside mount or choose a low-profile motorized option.

What happens if I send in one measurement instead of three?

Manufacturers build shade-to measurements to the narrowest point of your window. If you take only one measurement and it happens to catch a wide spot, the shade will be too wide to fit inside the frame, leading to returns and delays.

Should I measure for automatic shades differently than manual ones?

No—the width, height, and depth measurements are identical. The only extras for motorized shades are checking power source location, control-side preference, and clearance for the motor cassette above the window frame.