Curtain Fabric Calculator

Work out how much fabric curtains need from the window width, the fullness ratio, the drop and the pattern repeat.

Track or pole width in

Measure the track or the pole, not the window. Add the return to the wall if the curtains wrap around.

Finished drop in

From the bottom of the track or the eye of the ring to the finished bottom edge. Subtract 0.5 in for floor clearance if you want them just off the floor.

Fullness ratio

The header tape states the fullness it is designed for. Less fullness than the tape asks for gives flat, mean looking pleats.

Fabric width in

Curtain fabric is usually 54 in or 60 in. A narrow 44 in fabric needs more drops.

Header allowance in

About 8 in for pencil pleat tape, 10 to 12 in for a deep pinch pleat or a goblet heading.

Hem allowance in

8 in gives a double 4 in hem, which hangs better. 4 in is the minimum.

Vertical pattern repeat in

Measure between two identical points in the print. Leave at zero for a plain fabric.

Add lining

Lining is cut to the same drops and widths. Interlining goes in the same calculation.

The window needs a pair of curtains

Most windows are dressed with two curtains that meet in the middle. The total fabric is the same either way; this only changes the drops per side.

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Free calculator by Handcraft worked examples and methodology No account, nothing stored.