The Complete Guide to Measuring Your Windows for Perfect Fitting Window Treatments

Accurate measurements are the foundation of properly fitting window treatments. Whether you are working with an inside or outside mount, precision ensures your treatments function smoothly and look polished. Here is exactly how to measure your windows correctly.

Tools You Will Need

Gather a metal tape measure, a notepad for recording measurements, and a level to ensure accuracy. Avoid fabric measuring tapes that can stretch and provide inaccurate readings. Take measurements at multiple points since many windows are not perfectly square due to settling or age.

Measuring for Inside Mounts

Inside mounts fit within the window frame opening. Measure the width at three points: the top, middle, and bottom of the window. Write down the smallest measurement you find. For height, measure from the top of the interior frame to the sill, again taking measurements at the left, center, and right positions. Use the smallest height measurement to ensure your treatment fits properly without binding.

Measuring for Outside Mounts

Outside mounts extend beyond the window frame onto the wall or trim. Decide how far beyond the window you want the treatment to extend. Measure from where you want the left edge of the treatment to where you want the right edge. This typically means extending eight to twelve inches beyond the window frame on each side. For height, measure from where you want the top of the treatment to where you want the bottom.

Important Considerations

Check for obstacles like trim, molding, or built-in shelving that might interfere with your treatment. Verify that your window operates smoothly and test the full range of motion if applicable. Identify any unusual architectural features that might affect installation or operation.

Common Measurement Mistakes to Avoid

Never round measurements up; always round down to ensure proper fit. Do not measure just once; multiple measurements prevent costly errors. Avoid measuring from the outside of the window, as frame depth varies. Never assume symmetry; many windows sag or lean slightly over time.

Recording Your Measurements

Write down each measurement clearly, noting which position each represents. Include a sketch of your window shape and take photos from multiple angles. This documentation proves invaluable if questions arise later.

Investing time in accurate measurements prevents frustration and ensures your new window treatments fit beautifully and function perfectly from day one.