How to Measure for Vertical Blinds and Roller Shades in 4 Steps or Less

Window treatments come in all shapes, sizes, and styles, making it easier than ever to find the perfect blinds or shades for your home. The next step is making sure you get the right fit for your windows. Luckily, it’s not hard. We’ll walk you through how to measure for vertical blinds and roller shades so they fit like a glove.

Measuring Tip: Always round to the nearest ⅛ inch. 

Vertical blinds hang from the top to the bottom of a window. A sliding track system moves blinds to one side or splits them down the middle so that blinds open to both sides via a wand or pulley system. This type of blind is most commonly used for glass doors or wide windows. 

Before you measure your windows, decide whether you want vertical blinds that fit inside the window frame or are mounted outside the frame. Inside mount blinds do require a certain amount of depth in the window frame to work correctly. (Check manufacturer requirements for the blinds you wish to order.)

Outside mount blinds can cover ugly windows or make a window appear larger. Vertical blinds for sliding glass doors tend to be outside mount to maximize privacy.  

Measure the inside width at the top of your window where the blind will be mounted. Round down to the nearest ⅛ inch.

If there is molding around your window, measure to the far edges of the trim from left to right. If your window has no trim around it, determine how much extra width you want for light gap coverage and privacy (three to four inches on each side is a good amount), then measure from point A to point B with overlap included. 

Measure the exact height of your window in three places: the left side, in the center, and the right side. Write down the shortest of the three measurements.  

For a window with a protruding sill, start from the sill and measure up to a point two inches above the top of the window casing (for mounting hardware). For window sills that don’t protrude, begin your measurement two to three inches below the sill and measure up to two inches above the top of the window casing. Round to the nearest ⅛ inch.

Roller shades are window coverings with a single swatch of material that rolls up or down. They offer clean, modern lines and come in a variety of colors, patterns, and styles. In addition, they are typically easy to clean and operate. 

Choose whether you want roller shades that fit inside the window frame or are mounted outside the frame. Inside mount shades provide a beautiful framed look, while outside mount shades have increased light control and privacy.  

Measure the inside of your window opening from left to right at the top, middle, and bottom of the frame. Choose the narrowest measurement and round to the nearest ⅛ inch.

Decide how much overlap you want between your shade and window frame (at least 1.5 inches). Measure from point A to point B, taking that overlap into account. 

Measure the exact height of your window from the top of the opening to the sill, on the right, in the center, and on the left. Use the tallest of the three measurements and round to the nearest ⅛ inch.

Measure from the top of the window sill to where the top of the shade will be. If you do not have a protruding sill, measure from the top of where the shade will be mounted to where you want the shade to reach.

Measure the depth of the window casing at the top, middle, and bottom. Note any obstacles that could interfere with the shade function. Use the depth.

In a few simple steps, you now have the right measurements to get a perfect fit on your new vertical blinds or roller shades.