Curtain fabric calculator
Enter your pole or track width, drop and heading, and get the fabric widths, cut drop and total meters to buy, lining included.
Enter your numbers
How it is calculated
Curtains need more fabric than the window is wide, so the pole or track width is multiplied by a fullness ratio that depends on the heading: around 2.25 for pencil pleat, 2.3 for pinch pleat, 2 for eyelet, 1.75 for tab top, 2.1 for wave and about 1.1 for a flat panel. Add 20 cm for side hems and overlaps, divide by the fabric width and round up: that is how many fabric widths you need.
The cut drop is the finished drop plus 30 cm for the heading turnover and a proper double hem. If the fabric has a vertical pattern repeat, each drop must be cut at a whole number of repeats so the pattern matches across widths, so the cut drop is rounded up to the next full repeat. Widths times cut drop is the fabric to buy; lining needs the same widths at the finished drop plus 15 cm.
Worked example
A pair of lined pencil pleat curtains on a 200 cm pole, 220 cm drop, in 137 cm wide fabric with a 32 cm repeat: gathered width is 200 x 2.25 + 20 = 470 cm, so 4 widths. Cut drop is 220 + 30 = 250 cm, rounded up to 256 cm (8 repeats). Fabric: 4 x 256 = 10.24 m, so buy 10.3 m (about 11.25 yd). Lining: 4 widths x 235 cm = 9.4 m.
Common questions
- How much fabric do I need for eyelet curtains?
- Eyelet curtains hang best at about 2 times fullness. For a 150 cm pole with a 200 cm drop in plain 137 cm fabric, that is 3 widths at a 230 cm cut drop, so about 6.9 m. Run your own numbers above; eyelets also need an even number of rings per curtain, which your eyelet tape or kit will set.
- What is curtain fullness?
- The ratio between the flat width of fabric and the pole it covers. Fullness of 2.25 means the fabric is 2.25 times wider than the pole before it is gathered. More fullness gives richer, deeper folds and uses more fabric.
- How do I allow for a pattern repeat?
- Each drop must be cut at a whole number of vertical repeats so panels match side by side. The calculator rounds your cut drop up to the next full repeat; the offcut strip is normal and useful for tiebacks or cushions.
- Do curtains really need lining?
- Lining is optional but it protects the face fabric from sun, improves how curtains hang, and adds insulation. Blackout lining is calculated the same way; this tool's lining figure works for both.
- My numbers are in inches. Can I still use this?
- Yes, tap the inches button above the form and enter everything in inches. Results still show meters and yards, since fabric is sold both ways.
Related tools
SewCalc results are careful estimates based on standard practice. Fabrics, brands and personal technique vary, so always confirm measurements against your own pattern or project before cutting.