Home sewing · window treatments
Curtain fabric calculator.
Enter the track or pole width, the drop, the fullness and your fabric width. Get the number of fabric widths, the total length in metres and yards, and the lining. Inches or centimetres. Runs in your browser; nothing is sent or stored.
Window and fabric
Fabric to buy
Worked example
A 96 in track, 84 in drop, fullness 2, a pair of panels, 54 in fabric, 6 in header, 8 in hem and 1.5 in side hems. Flat width = 96 x 2 + 2 panels x 2 edges x 1.5 = 198 in. Widths = 198 / 54 = 3.67, rounded up to 4 (already even, so 2 per panel). Cut length = 84 + 6 + 8 = 98 in. Total = 4 x 98 = 392 in = 9.96 m = 10.89 yd.
Method
Plain arithmetic, no lookup tables. Flat width = track x fullness + (panels x 2 x side hem). Widths = flat width / fabric width, rounded up to a whole number; for a pair, rounded up again to an even number so both panels match. Cut length = drop + header allowance + hem allowance. With a pattern repeat, cut length is rounded up to the next whole repeat so the pattern matches across widths. Total length = widths x cut length. Lining uses the same flat width with its own fabric width and is cut to drop + hem allowance, assuming it stops at the heading.
Sources and conventions: inch and yard conversions use the exact definitions in NIST Special Publication 811 (nist.gov/pml/special-publication-811): 1 in = 2.54 cm, 1 yd = 0.9144 m. The fullness range, header, hem and side-hem defaults are common practice in curtain making, not a published standard; they are editable and you should use the figures from your heading tape, pleater or pattern instructions. As of 2026-10-02 this page cites no other tables.
Limits: seam allowances for joining widths, shrinkage and any extra for returns or overlap are not included; add them to the side hem or length allowances if your fabric needs them. Buy a little extra for cutting mistakes. Results are rounded up to the next hundredth of a metre or yard.
Frequently asked questions
How much fabric do I need for curtains?
Multiply the track or pole width by the fullness (for example 2 for double fullness), add the side hems, and divide by the fabric width, rounding up to whole widths. Each width is cut to the drop plus the header and hem allowances. Total fabric is the number of widths times that cut length.
What fullness should I use?
Fullness is how many times wider the fabric is than the track. Heading-tape and curtain-making guidance commonly runs from about 1.5x for light, flat looks up to 2x to 3x for pleated or sheer styles, but it is common practice, not a standard. Check the tape or pleat instructions you are using and enter that number.
Why does a patterned fabric need more length?
A pattern repeat has to line up across joined widths, so every width is cut to a whole multiple of the repeat. The calculator rounds each cut length up to the next full repeat, which is why a patterned curtain uses more fabric than a plain one.
How much lining do I need?
Lining gathers with the curtain, so it covers the same flat width. The calculator works out lining widths from the lining fabric width and cuts each to the drop plus the hem allowance, assuming the lining stops at the heading rather than folding into the header. Change the allowances if your method differs.
Do I measure the drop to the floor?
Measure from the underside of the pole rings or the top of the track gliders to where you want the curtain to end, and enter that as the drop. Floor length curtains usually finish a little above the floor so they do not drag; the exact clearance is your choice.
Can I get the answer in yards and centimetres?
Yes. Work in inches or centimetres and the result is shown in both metres and yards, rounded up to the next hundredth so you do not buy short. Conversions use the exact definitions, 1 inch = 2.54 cm and 1 yard = 0.9144 m.