Good curtains begin with good measuring, and most measuring mistakes are made in the same handful of places. Here is how to do it properly, and, just as important, when not to do it yourself at all.
Before you start
Use a metal tape measure, never a fabric one, measure in millimetres or centimetres rather than inches and fractions, and write everything down as you go, labelled by window. If a pole or track is not yet fitted, decide on it first: everything is measured from the pole or track, not from the window.
Measuring the width
Measure the full length of the pole between the finials, or the full length of the track. The pole or track should ideally extend 15 to 25cm beyond the window on each side, so the curtains can stack back off the glass and let all the light in. If you are quoting for a new pole, measure the window width and add that allowance.
Measuring the drop
Measure from the top of the track, or from the eye of the rings on a pole, down to where you want the curtain to finish:
- Sill length: about 1cm above the sill.
- Below sill: roughly 15cm below, clearing radiators where needed.
- Floor length: about 1cm above the floor for a crisp finish, the choice that flatters almost every room.
- Puddled: 2 to 5cm extra for a relaxed, romantic break on the floor.
Measure the drop at both ends and the middle: floors and sills are rarely level, especially in older houses, and the difference matters at floor length.
The classic mistakes
- Measuring the window instead of the pole or track.
- Forgetting radiators, sills, skirting boards and deep architraves that change where curtains can fall.
- Assuming both sides of a window, or both windows of a pair, are the same size. Measure every one.
- Ordering fullness too mean, which leaves curtains looking flat and skimped forever.
When not to measure yourself
Bay windows, arched and shaped windows, wave headings that need exact track calculations, and motorised systems should all be measured professionally, because errors there are expensive and unforgiving. This is why every Casa by Joanna project includes free professional measuring at home: you get precise windows and the responsibility for the numbers sits with the maker, where it belongs.