First decide: inside or outside mount?
Inside mount
The blind sits inside the window recess. Clean and tailored; shows off the trim; keeps the sill usable. Needs enough depth for the mechanism (a cassette or side channels need more) and a reasonably square opening. Small light gaps at the sides are normal — add channels for blackout.
Outside mount
The blind mounts on the wall or trim over the opening, larger than the window. Hides an out-of-square or shallow frame, makes the window look bigger, and gives better light block because the fabric overlaps the opening. The usual choice for curtains and Roman shades, and for blackout without channels.
Measuring an inside mount
- Width — measure three times. Top, middle and bottom of the recess. Frames are rarely square. Use the narrowest measurement.
- Height — measure three times. Left, centre and right, from the top of the recess to the sill. Use the longest for a blind that should reach the sill.
- Depth. Measure the recess depth. Each blind type needs a minimum depth to mount flush (a cassette or side channels need more). If it’s shallow, go outside mount.
- Check for obstructions — handles, cranks, tiles, alarm sensors.
- Don’t deduct anything. Give the exact opening size; the maker takes the correct clearance for that product.
Measuring an outside mount
- Width. Measure the opening and add overlap on each side — typically 5–8 cm per side (more for blackout).
- Height. Decide where the top will mount (above the frame) and where the bottom should end (sill, or below it), and measure between.
- Check the mounting surface is flat and solid, and that there’s room above the frame for the headrail.
Common mistakes we see
- Measuring once, in the middle only — then finding the top is 8 mm narrower.
- Rounding to the nearest centimetre. Millimetres matter.
- Deducting clearance yourself, then the maker deducts again → gaps.
- Forgetting depth — the cassette won’t sit inside the recess.
- Ignoring the handle that swings into the blind.
- Using a cloth or bent tape — use a rigid steel tape.
You don’t need to do any of this. Every My Kurtains order includes a free in-home measure by the people who will install it — we take responsibility for the fit. This guide is here so you understand what “made to measure” really means, and so you can sanity-check anyone else’s work.
Frequently asked questions
Do I measure the window or the blind size?
Give the exact opening size (for inside mount) and let the manufacturer make the deductions for that specific product — never deduct yourself, or you’ll double-deduct and get gaps.
Inside or outside mount — which is better?
Inside for a clean, tailored look if you have depth and a square frame. Outside to hide an out-of-square or shallow recess, make the window look larger, or improve light block.
How much overlap for an outside mount?
Typically 5–8 cm each side and above the frame; more if you want blackout without side channels.
Why measure width in three places?
Because window recesses are rarely perfectly square. Using the narrowest measurement ensures the blind fits everywhere.
Do you measure for me?
Yes — a free in-home measure is included with every order across Montreal, done by our installers.
