How to Measure Your Windows Correctly for Perfect Window Treatments

Gathering Your Tools

Accurate window measurements are essential for window treatments that fit properly and function smoothly. Poor measurements result in treatments that don't operate correctly or look unbalanced in your space. Learning to measure correctly saves time, frustration, and prevents costly mistakes.

Begin by gathering the right tools. You'll need a metal measuring tape, pencil, and paper. Metal tapes provide more accuracy than fabric ones since they don't stretch. Take all measurements at least twice to verify accuracy.

Measuring Width and Height

For width measurements, measure at three different heights: the top, middle, and bottom of the window. Buildings often settle, and window frames are rarely perfectly square, so these three measurements may vary slightly. Use the smallest measurement when ordering to ensure your treatments fit properly throughout.

Inside mount installations, where treatments fit inside the window frame, require measuring the width of the interior opening. Measure precisely at the top, center, and bottom. For height, measure from the very top of the opening down to the sill, checking multiple locations from left to right.

Outside Mount Considerations

Outside mount installations, where treatments extend beyond the frame, offer more design flexibility. Measure the full width including the wall space you want to cover on each side. Standard practice extends treatments six inches beyond the window frame on each side, but you can adjust based on your preferences. For height, decide where you want your treatments to start and end, then measure accordingly.

Consider the depth of your window frame when ordering. Deep frames or obstacles like radiators might affect installation options. Measure the distance from the wall to the window frame's outer edge.

Documenting Special Considerations

Take additional measurements around functional elements. Note the height of furniture below windows, radiators, air conditioners, or other obstacles that might interfere with your treatments. These measurements inform decisions about length and fullness. When measuring for multiple windows in the same room, treat each window individually rather than assuming they're identical. Even windows that appear the same may have slight variations.

Document everything carefully. Include window location, measurements taken at different points, and any special considerations. This documentation helps when consulting with specialists and provides reference information for future projects.

Double-check before ordering. Reviewing measurements one more time catches errors before installation. The small investment of time in accurate measuring ensures your window treatments look professional and operate flawlessly from day one.