To measure for 72-inch blinds, you measure the window opening itself, not the blind label, and order the size that matches your mount type.
Measuring for 72-inch blinds comes down to one rule: the window determines the size, not the product name. A “72-inch blind” refers to the width of the blind, but whether that fits your window depends entirely on how you mount it and how precisely you measure. Here is the process that works for inside and outside mounts alike.
Inside Mount vs. Outside Mount: Which One First?
Choose your mount type before you measure anything, because each one uses a different measuring rule. An inside mount sits within the window frame, offering a clean, built-in look. An outside mount covers the frame and part of the wall around it, which hides the frame and blocks more light.
Decide based on your frame and your light-control needs. If your frame is shallow or has obstructions like handles or locks, an outside mount may be the safer choice.
The Correct Way To Measure For Inside Mounts
For inside-mount 72-inch blinds, measure the width at the top, middle, and bottom of the window opening, then use the narrowest of the three numbers. Home Depot’s measuring guide confirms this rule. Then measure the height on the left side, in the middle, and on the right side, and use the longest height for most horizontal blinds and shades. The single most common mistake is reversing these rules—using the widest width or the shortest height.
Use a steel tape measure and read to the nearest 1/8 inch. A cloth tape can stretch and throw off your numbers. Do not round up to the nearest inch; manufacturers expect precise figures, and rounding can make a blind bind inside the frame.
Finally, check the depth at the top of the frame. This tells you whether the blind’s headrail will fit inside the opening. Compare that depth against the product’s minimum requirement, which is always listed in the product specs. Ignoring an obstruction like a window lock or a crank handle is a classic cause of a blind that will not sit flush.
Measuring For An Outside Mount
Outside mounts are simpler. Measure the full width and height of the area you want covered, then add the manufacturer’s recommended overlap on each side. Guidance commonly suggests about 2 inches per side, though some manufacturers specify at least 3/4 inch per side. Check the specific product’s measuring guide, because the overlap requirement varies.
The extra width ensures light does not leak around the edges and provides better privacy. For a 72-inch window, that means ordering a blind wider than 72 inches, so the “72-inch” label may not be the size you actually need.
Measuring Mistakes That Ruin The Fit
- Measuring once. Windows are rarely perfectly square. Take three width readings and three height readings, or you risk a crooked fit.
- Using the wrong dimension rule. Smallest width and longest height apply to most horizontal blinds and shades. Roller shades are the exception—they use the shortest height.
- Ignoring obstructions. Locks, levers, handles, molding, and tracks all reduce usable depth and clearance. Check every one before ordering.
- Rounding numbers. Keep exact measurements to the nearest 1/8 inch. Rounding to the nearest half-inch on a 72-inch blind can create noticeable gaps.
If your window measures out to a nonstandard size, our tested roundup of the best 72-inch blinds covers which products offer custom sizing and which brands stay true to the label.
| Measurement | Rule | Common Error |
|---|---|---|
| Inside width | Narrowest of top, middle, bottom | Using the widest reading |
| Inside height | Longest of left, middle, right | Using the shortest reading |
| Inside depth | Compare to product’s minimum | Skipping the depth check entirely |
| Outside width | Window width plus overlap on both sides | Ordering the exact window width |
| Tape type | Steel or metal only | Using a stretchy cloth tape |
| Precision | Nearest 1/8 inch | Rounding to the nearest inch |
The same core rules appear in Home Depot’s measuring guide and in the installation manuals published by Lowes’ blind manufacturers.
The last check before you order: confirm your height rule against the specific product. Most horizontal blinds and shades use the longest height, but roller shades use the shortest. If you are ordering a roller shade for a 72-inch-wide window, that one difference decides whether the shade fits or drags on the sill.
FAQs
What does a 72-inch blind actually measure?
A 72-inch blind refers to its width, not its height. The height is listed separately in the product specs. For an inside mount, that 72-inch width must match the narrowest width of your window opening, measured at the top, middle, and bottom.
Can I use a cloth tape measure for blinds?
No. Cloth tape stretches, which introduces error into a measurement that needs to be precise to the nearest 1/8 inch. Use a steel or metal tape measure for all blind measurements, and keep the tape flat against the frame.
What if my window measures 71.5 inches wide?
Order the size that fits your frame, not the nearest standard label. A 72-inch blind will not fit a 71.5-inch opening in an inside mount because it would bind. Check the manufacturer’s size options and order the width that matches your exact narrowest measurement.
References & Sources
- Home Depot. “How To Measure For Blinds And Shades.” Details the three-point width and height method for inside mounts.