How to Measure for Curtains
Measuring for curtains comes down to two numbers and where you take them from: the width of the track or pole, and the finished drop from the top of the heading to where you want the hem to fall. Get those right and a fabric calculator does the rest.
Fit the pole or track first
Measure the rail, not the window, because the curtains hang from the rail and have to clear the glass. Put the pole up first, about 15 to 20 cm past each side of the window so the open curtains sit off the glass, and 10 to 15 cm above the frame so the heading does not cover the view. Only then do you have a real width to measure.
The width
For a pole, measure between the two finials, the decorative ends, in a straight line. For a track, measure the full length of the track including any overlap arm in the middle. That single number is the track width the fabric calculator multiplies by your fullness. A pair of curtains shares that width, so you do not measure each side separately.
The drop
The drop is the finished length of the curtain, from the top of the heading down to the hem. Where you start depends on the heading:
- Pole with rings: start from the bottom of a ring, because the fabric top sits just under the ring.
- Eyelet on a pole: start from the top of the pole, since the eyelets sit over it.
- Track: start from the top of the track, or wherever the heading tape will sit.
Then choose where the hem lands: to the sill, about 1 cm above it; just below the sill, around 15 cm under; or to the floor, either kissing the floor or breaking by a centimetre or two for a softer look. Measure to that exact point. The calculator adds the header turn and the hem on top, so you give it the finished drop you actually want to see.
The fabric width
One more number matters: the width of the fabric roll. Curtain fabric is usually 137 cm (54 inches) wide, but it ranges from about 110 cm to 150 cm. Check the bolt before you buy, because the roll width decides how many widths you need, and a narrower roll can push you up a whole width. Enter the real width in the calculator rather than assuming.
Get a clean measurement
- Use a steel tape, not a fabric one, since fabric tapes stretch and read long.
- Measure twice and write it down. A mistake here is a mistake in metres of cloth.
- For wide windows, measure the pole at both ends and the middle in case the wall is not square.
- Decide your hem finish before you measure, not after.
With the pole width, the drop, and the fabric width in hand, the curtain fabric calculator turns them into widths, cut lengths, and a total. From there, read the fullness and pleat guide to choose a heading, and pattern repeat explained if your fabric has a design.
Frequently asked questions
Where do I measure curtain width from?
Measure the track or pole itself, not the window. For a pole, measure between the finials, the decorative ends. For a track, measure the full length of the track. This is the width the calculator multiplies by your fullness, so it must be the rail your curtains hang from, not the glass.
How do I measure the drop for curtains?
Measure from the top of where the curtain will hang to where you want the hem to fall. For a pole with rings, start from the bottom of the ring, since the curtain top hangs there. For eyelet curtains, measure from the top of the pole. Then pick a finish: to the sill, just below the sill, or to the floor.
How much wider than the window should curtains be?
The track or pole should extend about 15 to 20 cm, or 6 to 8 inches, past each side of the window so the curtains clear the glass when open and the room gets full light. Fit the pole first, then measure it, because the calculator works from the pole width.
Should curtains touch the floor?
It depends on the look you want. A hem that just kisses the floor is the most common and the easiest to keep clean. A break, where the fabric pools a centimetre or two, looks softer. Measure to the exact finish you want and the calculator builds the hem allowance on top.