Curtain Fabric Calculator
Work out exactly how much curtain fabric to buy. Set your pleat type, fullness, pattern repeat and lining, in inches or metric, then download a print-ready cut list.
How the calculator works out the fabric
The estimate follows the standard workroom method. First it finds the number of fabric widths: the track width times the fullness for your heading, divided by the usable width of one drop. A pencil pleat or a wave heading uses about 2 times fullness, a triple pinch pleat about 2.5, an eyelet heading about 1.6 (fabricforhome.com, janeclayton.com).
Then it sets the cut length for each width: your finished drop plus the header turn hidden behind the heading, plus the bottom hem. For a patterned fabric it rounds that length up to a whole number of pattern repeats so every width starts at the same point in the design. A half-drop repeat adds one extra whole repeat to the order, once, to cover the alternate drops (sew-helpful.com). Multiply the widths by the cut length and you have the total fabric to buy.
Want the detail behind each input? Read how to measure for curtains, the fullness and pleat guide, and pattern repeat explained.
A worked example with real numbers
Here is the job the calculator opens with: a pair of triple pinch pleat curtains on a 200 cm track, a finished drop of 230 cm, fabric 137 cm wide with a 64 cm half-drop repeat, a 15 cm double bottom hem, and 5 cm side hems. Step by step:
- Widths. 200 cm of track times 2.5 fullness is 500 cm of fabric to gather. Each width gives 137 minus two 5 cm side hems, so 127 cm of usable cloth. 500 divided by 127 is 3.9, rounded up to 4 widths, 2 per curtain.
- Cut length. The 230 cm drop, plus a 20.3 cm header turn for a pinch pleat, plus the 15 cm hem doubled to 30 cm. That is 280.3 cm.
- Repeat rounding. 280.3 divided by the 64 cm repeat is 4.4, so each width is cut at 5 whole repeats: 320 cm.
- Half-drop allowance. One extra repeat, 64 cm, added once for the whole order.
- Total. 4 widths times 320 cm plus 64 cm is 1344 cm. You order 13.44 m, about 14.7 yards.
The same pair in a plain fabric needs 4 times 280.3 cm, which is 11.21 m. So the 64 cm half-drop repeat costs about 2.2 m of extra cloth here, and that allowance is the number most calculators drop. Run the defaults above and you will see these exact figures.
What this calculator does not do
A few things sit outside the estimate:
- It plans the fabric to order, not a sewing pattern. It does not lay out seams, piecing, or where the pattern falls on each drop.
- The repeat it needs is the vertical repeat from the bolt label. A horizontal repeat does not change the length you buy.
- It covers curtains only. Roman blinds, pelmets, tiebacks, and upholstery need different math.
- Lining is estimated as plain widths cut a little shorter than the face fabric. Your workroom may cut it their own way.
Frequently asked questions
How much fabric do I need for curtains?
Multiply the track or pole width by the fullness for your heading (about 2 for pencil pleat or wave, 2.5 for a triple pinch pleat), then divide by the usable fabric width to get the number of widths. Each width is cut to the finished drop plus the header turn and bottom hem, rounded up to a whole pattern repeat if the fabric has one. The calculator above does all of this and gives you the total in yards or metres.
Does this work in both inches and metric?
Yes. Use the inches and yards toggle for US measurements, or switch to cm and metres for UK, Australian, and European fabric. The math is the same, the calculator just converts the units for you.
How does it handle a half-drop pattern repeat?
A half-drop repeat steps the pattern down on alternate widths, so you add one whole extra pattern repeat to the order once, not per width. Half of that repeat positions the pattern and half offsets the alternate drops. Set the repeat to half-drop and the calculator adds the allowance for you, which is the part most calculators get wrong.
What is the cut list PDF?
It is a print-ready sheet listing every drop to cut and its exact length, including the header turn, hem, and pattern repeat, plus the total fabric to buy. Take it to the fabric shop or your workroom and cut straight from it. It is generated in your browser from your numbers, so nothing is sent anywhere.
Should I buy extra fabric?
Yes, a little. Buy 5 to 10 percent over the estimate to cover a fault in the cloth, a miscut, or a future repair. The calculator rounds widths and repeats up, which already builds in some safety, but cloth is cut by hand and mistakes happen.