This guide covers every made-to-measure shade we build: roller, Roman, zebra, solar, cellular and woven wood. Measuring a shade is simpler than measuring a shutter. There are two numbers, and which two depends on one decision.
Before you start
- Use a steel tape or a laser measure. Not a cloth tape: it stretches, and a stretched tape reads long.
- Measure the window itself, not a shade already hanging there.
- Measure every window separately, even when two look identical. Openings are rarely as square as they appear.
- Round to the nearest 1/8". In our configurator, whole inches go in the first box and eighths in the one beside it, so 36 1/2 is 36 with 4/8.
- Width first, then height. It is the order every blind and shade is written in, and one ordered the other way round has to be made again.
Inside or outside mount?
An inside mount sits the shade in the window recess, so it looks built in. An outside mount sits it on the wall or frame above the opening, which covers more glass and lets less light past the edges.
The two want different numbers, and this is the most expensive thing to get wrong:
- Inside mount: give us the bare opening. We take the manufacturing deductions off ourselves so the shade clears the frame and runs freely.
- Outside mount: give us the finished size you want. We build exactly what you type and take nothing off.
Measuring for an inside mount
- Width. Measure across the opening in three places: near the top, halfway down, and near the bottom. Give us the smallest of the three. A shade cut to the widest one will not go in.
- Height. Measure from the top of the opening down to the sill on the left, in the middle and on the right. Give us the largest of the three, so the shade reaches the sill on the low side.
- Depth. Measure from the face of the opening back to the glass. See the table below.
Give us those numbers exactly as measured. Taking the deductions off yourself as well leaves a gap down both sides.
How much depth do I need?
Depth almost never rules out an inside mount. What it decides is how far the head sits proud of the opening, not whether the shade fits at all.
| Shade | Sits flush at | Will still mount at | Bracket |
|---|---|---|---|
| Roller, Roman, zebra, solar | 3" (the cassette) | 1" | 55 mm |
| Cellular | the head rail depth | 1/2" recommended | 40 mm |
| Woven wood | 45 mm (about 1 3/4") | 1/2" | 45 mm |
So a roller shade in a 2" recess still mounts; the cassette simply stands an inch proud of the opening. Below the flush figure you are choosing how much it projects, and that is a look, not a fault.
Check the recess is clear of anything the shade would have to sit in front of: window cranks, handles, locks, alarm boxes, flyscreens. If an inside mount would put the shade over one of those, measure from the front of the obstruction instead, or switch to an outside mount.
Measuring for an outside mount
Here the overlap is the point, so you add it and we build what you give us.
- Measure the opening, width and height, the same way as above.
- Add 4 inches to the width and 4 inches to the height. That is 2 inches of overlap on each side, which is what stops light leaking down the edges. Working in millimeters, add 100 mm to each.
- Look above the opening. You need a flat run of wall or frame for the brackets, and enough clear width either side for the overlap to land on something solid.
Type in the total, overlap included. That is the size we build. Want it wider or taller than that, to clear a sill or line up with something? Give us that instead.
Where the fabric sits inside that width
On an outside mount we take nothing off the size you give us, but the fabric itself is slightly narrower than the shade. It is worth knowing before you decide how far past the opening to go, because it is the difference between the overlap you chose and the overlap you get.
| Shade | Each side | Chain side, with a chain loop |
|---|---|---|
| Roller, zebra, solar | 3/8" | 3/4" |
| Roman | 1/4" | 5/8" |
| Cellular | 2 mm (about 1/16") | not applicable |
| Woven wood | none | not applicable |
A roller shade ordered 40 inches wide carries 39 1/4 inches of fabric across it. Choose a chain loop and the chain side takes 3/4" instead, because the mechanism sits there. On woven wood there is no deduction at all: the width you give us is the width of the panel, measured to its outside edges.
ZeroGlow blackout shades
ZeroGlow fits inside the frame and is not offered as an outside mount, so there is only one set of numbers to give us: the opening itself, measured as above. We take the manufacturing deductions off to leave it running clear.
One last check
If a measurement lands right on one of our size limits, measure it a second time before you order. The configurator will tell you if a size cannot be built, but a number that is right at the edge is the one worth double checking.
Still unsure? Send us a photo of your window and our team will help. We also review every order before manufacturing begins.