Curtain Fabric Calculator
Enter your track or pole width, the finished drop, the fullness your heading style needs, and the fabric roll width. The calculator works out panel count, cut length with hem and heading allowances, and total metres to buy.
Fabric-shop calculators assume one window and hide the allowances. This one shows the 30 cm per panel that proper hems eat, and why fullness - not window size - is the number that moves the bill.
How to use
- Measure the track or pole, not the window: pole width plus finials is the working figure, fitted where the curtain will hang.
- Measure finished drop from ring eye or track to the intended hem line - sill, radiator top or floor, minus 1 cm clearance.
- Pick fullness by heading: 2× for pencil pleat, 2.5× for pinch pleat, 1.5× for eyelet flats, then read panels and metres.
Frequently asked questions
How much fabric do I need for standard curtains?
A 150 cm track at 137 cm drop in pencil pleat takes about 5.2 m across 3 panels of standard 137 cm fabric. The counterintuitive part: doubling the window width less than doubles the fabric when panels already overshoot the roll width.
What is curtain fullness?
The ratio of gathered fabric width to track width. Pencil pleat wants twice the track width to fold into crisp columns; pinch pleat needs two and a half for the fixed pleats; eyelet headings manage with one and a half because each wave uses less cloth.
Why add 30 cm per panel?
A double-turned 15 cm bottom hem gives the weight that makes curtains hang in folds instead of flapping, and the heading allowance tops the panel. Skimp on both and the curtain looks home-made from across the room, whatever the fabric cost.
How does pattern repeat change the maths?
Each drop must start at the same point of the pattern, so add one repeat per panel beyond the first and buy from one dye lot. Solids and tone-on-tone weaves skip this entirely - one reason plain curtain fabric is cheaper to make up than it looks.