Nothing spruces up a window space as a new set of blinds, and the most popular choice when installing new blinds is to mount them inside the window frame. The most important part of installing new blinds is to order the correct size. If installing the blinds yourself, you will need to know how to measure windows for blinds.
To measure windows for blinds, follow these steps: Measure the overall width of the window opening at the top, middle, and bottom. Measure the height of the window opening at the left, middle, and right-hand sides. Use the narrowest width and the longest height measurement when ordering new blinds.
Outside mounts are preferred when there are obstructions inside the frame, such as window handles, or when there is inadequate frame depth to mount the blinds inside the window frame. Some people opt to install their blinds with additional overhangs to increase privacy and minimize light gaps. Below are step-by-step instructions on how to accurately measure windows for blinds.
Related: How to Measure Windows for Curtains
- Steel tape measure
- Step ladder
- Pencil or pen
Step 1: Measure the Width of the Window Opening at the Top
The first step when measuring windows for blinds (inside mount) is to get on the step ladder armed with the steel tape measure. Take the top measurement of the inside of the window opening.
To ensure accuracy, do the measurement a couple of times before writing the total down on the piece of paper.
Top Tip: When using the steel tape measure to measure the overall height and width of the window frame, ensure that you round measurements to the nearest1/8" to ensure the most accurate measuring results.
Step 2: Measure the Width of the Window Opening in the Middle
The second step involves measuring the middle part of the window opening. Take a few measurements until you're satisfied with the accuracy. Take a pencil or pen and write the total down on the paper.
Step 3: Measure the Width of the Window Opening at the Bottom
The third step involves the final width measurement. Make your way to the bottom part of the window opening and measure the width. Again, take the measurement several times until you are sure of the number. Take the piece of paper and record the measurement on the piece of paper.
Step 4: Use the Narrowest Width Measurement
Take the paper and study the three width measurements you recorded for the window opening's top, middle, and bottom. Identify the narrowest measurement and use it as your overall width.
You will achieve the best results when moving the new blinds up and down using the narrowest measurement.
Step 5: Measure the Height of the Window Opening on the Left
When you have successfully measured the width of your window opening, it’s time to measure the height. Make your way up the step ladder and measure the left-hand side of the window opening from top to bottom.
Place the beginning of the steel tape measure on the bottom part of the window opening and measure the top of the left-hand side of the window opening. Try to take the measurement at eye level to ensure accuracy. Write the measurement total down on a piece of paper.
Step 6: Measure the Height of the Window Opening in the Middle
After taking the height measurement on the left-hand side of the window opening, make your way to the middle of the window opening and take the measurement as you did in step 5. Make a note of the measurement total on the piece of paper before moving on to the next step.
Step 7: Measure the Height of the Window Opening on the Right
Make your way to the right-hand side of the window opening and measure the height from top to bottom. When you are certain of the measurement total, write it down on paper.
To ensure that the measurement process was done perfectly, it's not a bad idea to repeat the steps for peace of mind, ensuring that the figures correspond the second time of asking.
Top Tip: If you're one of the people who prefer that their blinds don't rest directly on the bottom of the window opening (sill), then all you have to do is subtract ¼" from the longest height measurement. Suppose the window has no sill; then measure to the point where you want your new blind to reach.
Step 8: Use the Longest Height Measurement
Study the three height measurements that you have dotted down. Pick the longest height measurement to calculate the overall height requirement of the new blinds. When equipped with the narrowest width and longest height measurement, you can order your new blinds.
Following the abovementioned steps, the new blinds should fit like a glove when they arrive at your home. Follow the blind manufacturer's instructions to the letter when performing the installation to ensure the perfect fit and a beautiful "new" window space.
Top Tip: Before ordering your new window blinds, measure the window opening on the diagonal (from the top corner to the bottom corner on the opposite side). Should the diagonal measurements differ greatly, it may be better to install outside mount blinds for light leakage and privacy reasons.
How to Measure a Window for Outside Mounted Blinds
Some window designs make it impractical to fit blinds inside the window frame. Obstacles such as window handles and burglar bars can force you to opt for outside mount blinds instead.
When protrusions come into play, you may need to use spacer blocks or extender brackets to navigate the problem.
The advantage of mounting blinds outside the window opening is that it provides extra privacy and minimizes light gaps. Here's a quick breakdown of how to measure a window for outside mount blinds:
- Take the steel measure tape and measure the wall above the window opening. Measure the distance from the furthermost points that the blind need to cover. Blinds should overlap the window opening by a minimum
of 1 ½" on each side. A combined overlap of 3" on the width will ensure that light leakage is kept to a minimum. Write the measurement total down on a piece of paper.
- Measure the distance from the top point, where the blind will be located, to where it will come to rest (typically on the window sill.) The blinds must overlap the top of the window opening by a minimum of 1-½". However, some products may require a bigger overlap to accommodate mounting hardware.
- If you prefer the blind to extend past the window sill (not recommended when it is protruding), or if there's no window sill, measure to the point where you would like the blind to reach and jot it down on the piece of paper. If the blind is to extend to the floor area, ensure that you subtract ½" from the height measurement.
Top Tip: To combat light leakage, and add to your overall privacy, ensure that the blinds overlap the window opening by 4" on both sides (8" in total width). By making the blinds extend 3" above and below the window opening, you don't have to worry about certain blind manufacturers' space requirements for mounting hardware.
How to Measure a Window for Inside Mount Vertical Blinds
The process when measuring a window to fit vertical blinds inside a window opening is similar to the one listed above when fitting horizontal blinds, with a few
exceptions to the step-by-step process listed above. Here's a quick overview of the process:
- Use the steel tape measure to measure the width of the window opening. When installing vertical blinds, you're only required to measure the width of the top of the window opening.
- Measure the window opening height on the left, middle, and right-hand sides. Instead of recording the longest height measurement as we did when measuring for horizontal blinds, we take the shortest height measurement as our order measurement figure.
- You must forward the exact measurements to the blind company with no deductions from the original measurements. The blind factory will consider deductions during the production process.
To recap, when fitting vertical blinds or solar shades, you will only measure the top of the window opening for the required width measurement.
The shortest height measurement between the window opening's left, middle, and right-hand side is to be used when fitting vertical blinds, sheer shades, roller shades, or solar shades.