Sizing Guide: How to Measure Your Window For Roman Shades. Inside & Outside Mount Explained
Off-the-shelf shades rarely fit an old or odd window — that's the whole reason we make yours to measure. Get the numbers right once and the rest is easy: we take the mount deductions for you, sew to a quarter of an inch, and send a sketch to approve before we cut. Here's how to measure any window or French door.
- Watch the guide
- What you'll need
- Inside or outside?
- Measure: inside mount
- Measure: outside mount
- Ready to order
What you'll need
Tools
- A steel tape measure (not cloth — it stretches)
- A pen and paper
- A stable step ladder
Measure the window opening itself, never your existing shades. And measure each window on its own — even the ones that look identical.
On the ladder
- Open it fully on firm, level, non-slip ground and lock the braces.
- Face the ladder; keep three points of contact and a hand on the rail.
- Have someone pass you the tape and paper if that feels safer.
Inside or outside mount?
This is the first decision — it changes how you measure. Check your window before you pick.
Sits inside the frame
The shade fits within the window frame, showing off the molding for a clean, built-in look — and it helps with insulation.
Choose it when your frame is at least 1.5–2" deep, so the shade doesn't stick out.
Mounts on the trim or wall
The shade sits over the molding or on the wall above the opening. It covers light gaps, adds privacy, and hides a frame that isn't square.
Choose it when you have about 3" of wall above the opening — or your window isn't square (measure the diagonals; if they don't match, go outside).
Either way, we can make it. Not sure which suits your window? Ask us — we'll help you decide.
How to measure for an inside mount
If your casing allows it, here's how to get an exact inside-mount fit.
Width
Measure the inside of the frame left to right in three places — top, middle, and bottom. Round each to the nearest 1/4" and use the narrowest number. That's the width you send us.
Height
Measure top to sill in three places — left, middle, and right. Round to 1/4" and use the tallest. Want the shade to clear the sill instead of resting on it? Take 1/4" off the final height.
Don't deduct — we do it for you
Send the opening size as measured. We make the inside-mount allowances in our workroom so the shade fits the opening cleanly. Double-check your numbers and record them as W × H × D (width × height × depth).
How to measure for an outside mount
If your window is better suited to an outside mount, here's how to measure it right.
Width
Measure across the casing — top, middle, and bottom. Round to 1/4" and use the largest. Then add 0.5–1" on each side to cover the frame and block side light.
Height
Mark where you want the top to sit — at least 3" above the casing, so the mechanism clears the trim. Prefer the stack not to block your view when the shade is up? Add 10–12" above the opening. Measure from your mark down to the sill on the left, middle, and right; round to 1/4" and use the largest. No sill? Add 1" at the bottom to avoid a light gap.
Double-check
Confirm your numbers and record them as W × H × D so nothing gets mixed up.
The rules, in one place
- Always record W × H × D, rounded to the nearest 1/4".
- Measure in three spots: use the narrowest for inside mounts, the widest for outside.
- Measure each window separately — even matching ones.
- For inside mounts, don't deduct. We make the allowances for you.
Ready to order — or want a second pair of eyes?
Send us your numbers and we'll check the fit, then send a sketch to approve before we cut. If our mistake makes it wrong, we remake it. And if you're unsure about a colour, order swatches first — seeing the linen in your own light is the surest way to decide. Here's what happens if a measurement comes in off.
Sewn to 1/4" in our Toronto workroom · ships in 10 days or less · 2,000+ five-star reviews.