Circle Skirt Calculator — Fabric & Pattern Measurements
Enter your waist measurement, desired skirt length and style (full, half or quarter circle) to get the exact inner radius, outer radius, hem circumference and minimum fabric square — with seam allowance built in.
cm
cm
Skirt style
cm
Smallest square of fabric that fits the complete skirt piece
- 1
Inner (waist) radius
70 ÷ (2 × π × 1) = 11.14The arc of the inner hole at this fraction of the full circle equals the waist measurement. - 2
Outer (hem) radius
11.14 + 60 = 71.14 - 3
Outer cut radius
71.14 + 1.5 = 72.64 - 4
Fabric square side
2 × 72.64 = 145.3
How does this calculator work?
Inner radius = waist ÷ (2π) for a full-circle skirt (divide by π for half, π/2 for quarter). Outer radius = inner radius + skirt length. Minimum fabric square side = 2 × outer radius + seam allowance. Enter waist, length and style to get exact cut dimensions.
Formula
How this is calculated
A circle skirt is cut from a flat ring of fabric called an annulus. The inner hole forms the waist opening and the outer edge becomes the hem. To calculate the inner radius, divide the waist circumference by 2π for a full-circle skirt, by π for a half circle, or by π/2 for a quarter circle. Add the desired skirt length to get the outer radius.
The minimum fabric square is the smallest piece of fabric from which you can cut the full ring: its side equals 2 × outer radius (with seam allowance). A full-circle skirt requires a square folded into quarters; a half-circle fits in a single rectangle of 2r × r. Seam allowance is added inward at the waist (so you can attach the waistband) and outward at the hem (for the hem fold).
Fabric stretch, pattern matching, grain line direction and fabric width are not accounted for. Woven fabrics need careful grain alignment; knits can often be cut on the bias. Always measure twice and cut once — add an extra 2–3 cm beyond the seam allowance if you want a safety margin.
Frequently asked questions
A quarter-circle skirt uses the smallest bounding square and therefore the least fabric, but produces a more fitted silhouette with less flare. A full-circle skirt needs the largest square but creates the widest, most dramatic sweep at the hem.
The calculator adds the seam allowance for you. Cut the inner (waist) circle at inner radius − seam and the outer (hem) circle at outer radius + seam. The "fabric square side" value already includes the seam allowance.
Yes — enter all measurements in inches and all results will be in inches. Just keep the unit consistent: do not mix centimetres for the waist and inches for the length.
Also known as
TG we-Calculate Editorial Team. (2026). Circle Skirt Calculator — Fabric & Pattern Measurements [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/circle-skirt-calculator
TG we-Calculate Editorial Team. "Circle Skirt Calculator — Fabric & Pattern Measurements." TG we-Calculate. 2026. https://we-calculate.com/calculator/circle-skirt-calculator.
TG we-Calculate Editorial Team, "Circle Skirt Calculator — Fabric & Pattern Measurements," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/circle-skirt-calculator
@misc{wecalculate_circle_skirt_calculator, title = {Circle Skirt Calculator — Fabric & Pattern Measurements}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/circle-skirt-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?