How To Measure For Horizontal Blinds

Inside Mount
If you are going to mount the blinds inside the window frame (called an inside mount or a recessed mount), follow these steps:

1. Measure the width of the window opening from side-to-side, measuring to and from the inside trim on both sides.
2. You will want to take this same measurement in three places, simply because your window is probably not perfectly square. Rest assured, this is quite normal. For the most accurate measurements, you will want to measure the top, middle, and bottom areas.
3. You will use the smallest measurement when ordering your blinds. Generally, the manufacturer will deduct a small amount from the inside measurement to ensure clearance. If not, you can take the smallest measurement and round it down by 1/8”.
4. Next, measure the height of the window opening from the inside of the trim, stretching the tape measure vertically (from top to bottom or bottom to top), or to the exact length you want your blind.
5. Again, you will want to take this same measurement in three places (left side top-to-bottom, middle top-to-bottom, and right side top-to-bottom), simply because your window is probably not perfectly square. Once again, rest assured, this is quite normal. For the most accurate measurements, you will want to measure the right side, the middle, and the left side of the window.
6. For this measurement, you will want to take the largest of the three measurements and round it up by 1/8”.
7. Next, measure the available depth of your window frame (for slat size information and to ensure you have room for the mounting hardware). Note: You do NOT want to include inside trim in this measurement. Instead, measure only the space that is available to install the mounting hardware for your new blinds.

Outside Mount
If you are going to mount your new blinds outside the window frame, which means the mounts for your blinds will be placed outside the window opening either on the window’s wood frame/trim or above and on either side of the wood trim/frame, follow these steps:

1. Measure the exact width of the window’s frame from outside edge to outside edge, making sure to measure where your blinds will be mounted and positioned from.
2. Next, measure the exact height from the outside edge of the top of the trim to the top of the windowsill or to the exact length that you want the blind to hang. Note: Outside mounted blinds only require width and length measurements. The hardware included for outside mounts takes into account the varying sizes window blind slats.

Quick Tips

• All window blinds measurements are taken to 1/8-inch accuracy.
• Always round down to the closest 1/8-inch on window blind width measurement.
• Always round up to the closest 1/8-inch on window blind length/height measurement.
• Most blinds are available in a variety of slat widths. Popular slat width sizes include 1/2-inch micro, 1-inch mini, 2-inch, 2-1/2 inch.
• Inside mounting of your window blinds requires you measure for the slat size (depth), while outside mounting does not.
• With horizontals, wood blinds, pleated and cellular shades, it is generally recommended to add at least 1" to 3" beyond each side of the window and at least 2 ½" to 3" to the height to allow space for mounting brackets above the opening of the window and to add your desired overlap at the bottom of the window opening.

Need More Help?
Let us help you find a local installer who will handle the measuring and installing of your new window blinds for you.