Getting your measurements right is the difference between window coverings that fit properly and ones that leave gaps, sit crooked, or jam when you try to operate them. Most measurement mistakes happen because people confuse inside mount and outside mount, or because they measure once instead of three times.
Inside mount means the blind or curtain sits inside the window recess. The covering is flush with the wall, which looks clean and does not project into the room. For inside mount, you need to measure the width at the top, middle, and bottom of the recess, and use the narrowest measurement. Window recesses are rarely perfectly square, so the narrowest point stops the blind from jamming.
Outside mount means the covering sits on the wall above and around the window frame. This works when the recess is too shallow for an inside mount, when you want to make the window look larger, or when you are mounting curtains on a track above the frame. For outside mount, measure the area you want to cover and add overlap on each side. Most blinds need 50mm to 75mm extra on each side to block light bleed.
For curtains, you measure differently. The track or rod position determines the width. Curtain fabric is ordered wider than the track to allow for fullness. Sheer curtains typically need double the track width in fabric. Blockout curtains need about 1.5 times the track width. The drop measurement goes from the track to where you want the curtain to finish, usually floor length minus 10mm clearance.
A few mistakes to avoid:
Do not measure with a fabric tape. Use a steel tape measure for accuracy. Do not assume all windows in the same room are the same size. Measure each one individually. Do not round up. Give us the exact measurement and we will make the adjustments during manufacturing.
We offer free in home measurement as part of every consultation. Our team measures every window to the millimetre and handles all the technical calculations. If you want to do preliminary measurements yourself to get a rough quote, the guide above covers the basics. But for the final order, professional measurement is the safest option.
We manufacture all blinds and curtains to your exact window dimensions at our own facility, so the fit is precise every time.