How to Measure Windows for Blinds — Step by Step

Prefer hands-on help? Book a free professional measurement — we bring laser-precision tools to your home.

To measure a window for blinds: measure the inside width at three points (top, middle, bottom) and the inside height at three points (left, center, right), recording each to the nearest 1/8 inch. Use the smallest width for inside mount. The entire process takes about 15 minutes with a steel tape measure.

Measure from the front edge of the window frame to the back. Most products require:

Decide how far beyond the frame you want coverage. Standard overlap is 2–3 inches on each side for privacy and light control.

Measure from the top mounting point (above the frame) down to where you want the product to end. For floor-length treatments, measure to 1/2" above the floor.

Record what the brackets will attach to: drywall, wood trim, plaster, brick, or concrete . This determines the hardware needed.

Frequently asked questions

Do I measure the window or the frame?

For inside mount, measure the inside of the window frame (width and height at three points). For outside mount, measure the area you want to cover, adding 2–3 inches on each side for overlap.

What tools do I need to measure windows?

A steel tape measure (not cloth), a pencil, paper, and a step stool. A laser measure provides even more accurate readings for large windows.

Should I round up or down on measurements?

For inside mount, always record exact measurements to the nearest 1/8 inch. The manufacturer makes factory deductions. For outside mount, round up to ensure full coverage.

What if my window isn't perfectly square?

Most windows aren't. Measure width at three heights (top, middle, bottom) and height at three positions (left, center, right). Use the smallest measurement for inside mount to ensure the product fits.

Can Blinds Concept measure for me?

Yes — we offer free professional measuring as part of our consultation service. This is the most accurate option and eliminates measurement errors that can delay your order.

What's the minimum frame depth for inside mount?

Most blinds and shades require 2–4 inches of depth. Roller shades can fit as shallow as 1.5 inches. If your frame is too shallow, outside mount is the better option.

How do I measure an arched or specialty window?

Measure the width at the widest point and the height from the sill to the top of the arch. For most specialty shapes, a template or professional measurement is recommended.

Do I need to account for tile or baseboard?

Yes. For outside mount, measure from where you plan to install the bracket down to where you want the product to end. Note any baseboards, tile, or sill protrusions that could interfere.