Sewing Calculators
Ruffle fabric.
Enter the finished length the ruffle must cover, how full you want it and its depth. The calculator gives the cut length of the gathered strip, how many strips you join across your fabric width, and the yardage to buy. Runs in your browser.
Ruffle size
Fabric needed
Fill the form and press Calculate.
Answer
A ruffle that must cover 100 in at 2x fullness needs a gathered strip about 201 in long. Cut 5 strips across 42 in fabric, each 7.5 in deep, which is 1.125 yd.
Worked example
Finished length 100 in x 2 = 200 in gathered, plus 0.5 in at each end to turn under = 201 in. Each strip is 42 in wide and each join uses 2 x 0.5 = 1 in, so 5 strips give 5 x 42 - 4 x 1 = 206 in, enough; 4 strips would give only 165 in. Cut depth = 6 + 0.5 + 1 = 7.5 in. Fabric = 5 x 7.5 = 37.5 in = 1.04 yd, so buy 1.125 yd.
How it works
Gathered length = finished length x fullness ratio. Fibre2Fashion gives the rule of thumb that sheer fabrics need three times the finished length and weightier fabrics two and a half times; how full to make it is a style choice, so treat the ratio as a rule of thumb, not a standard. Strips across the fabric width are joined with seams, each join using two seam allowances of length. Cut depth is the finished depth plus the top seam and hem allowances. Yardage is strips x cut depth / 36, rounded up to the next 1/8 yd. Grain direction, patterns and a cut across the fabric (rather than along it) can change the amount, so treat this as an estimate.
Sources (opened 2026-10-08): Making Ruffles, So easy When You Know How! (Fibre2Fashion).
FAQ
How long should I cut a ruffle strip?
Multiply the finished length by the fullness ratio. At 2x, a ruffle covering 100 in needs a 200 in gathered strip, plus seam allowances at the ends.
What gathering ratio should I use?
It is a style choice. Fibre2Fashion gives 3x for sheer fabric and 2.5x for heavier fabric as a rule of thumb; use a lower ratio for a flatter look and test on a scrap.
How much fabric do I need for a ruffle?
Gathered length divided across your fabric width gives the strips, and each strip is the ruffle depth plus seam and hem allowances deep. The calculator adds these up and rounds to 1/8 yard.
Do the joins between strips matter?
Yes, slightly. Each join uses two seam allowances of length, so a long ruffle may need one more strip than the plain division suggests.
What is the hem allowance field?
The total fabric the hem uses, for example 1 in for a narrow folded hem. Enter 0 if the edge is finished another way, such as with a serger.
Disclaimer
Informational arithmetic for sewing. Cut a test strip in your fabric to check the fullness before cutting everything.