How do I cut a circle skirt?
Enter your waist and the skirt length, and pick a full, 3/4, half or quarter circle. The circle skirt calculator gives the radii to mark and the fabric you need.
- Fabric rectangle, length
- 52.91 in
Cut a waist radius of 4.456 in and an outer radius of 26.46 in; the pattern needs a 52.91 in by 52.91 in piece of fabric.
- Waist radius
- 4.456 in
- Outer radius
- 26.46 in
- Hem circumference
- 166.2 in
- Fabric rectangle, width
- 52.91 in
Fabric rectangle, length: 52.91 in. Cut a waist radius of 4.456 in and an outer radius of 26.46 in; the pattern needs a 52.91 in by 52.91 in piece of fabric.
Fabric rectangle, length by skirt length
How to calculate
Computes the waist radius, the outer radius, the hem circumference and the fabric rectangle for a full, 3/4, half or quarter circle skirt from the waist measurement and the skirt length.
Example with the default inputs (Skirt Full circle, Waist 28 in, Skirt length 22 in): Cut a waist radius of 4.456 in and an outer radius of 26.46 in; the pattern needs a 52.91 in by 52.91 in piece of fabric.
Method: waist radius r = waist ÷ (2π × f), f = 1, 3/4, 1/2 or 1/4; outer radius R = r + length + allowance; hem = 2π(r + length) × f; fabric rectangle = 2R × 2R (full, 3/4), 2R × R (half), R × R (quarter).
- The waist measurement already includes any ease; the waist seam allowance is part of the optional allowance, added to the outer radius only.
- The pattern is cut in one piece; a skirt wider than the fabric is cut in more pieces, which needs seam allowance at each seam.
- Fabric stretch and bias drop at the hem are not included.
Worked examples
Each example is checked against the calculator on every build.
- Skirt Full circle, Waist 28 in, Skirt length 22 in gives Waist radius 4.456 in, Outer radius 26.46 in, Hem circumference 166.2 in, Fabric rectangle, width 52.91 in, Fabric rectangle, length 52.91 in.Source: Circumference of a circle C = 2πr (OpenStax Prealgebra 2e, section 9.5, https://openstax.org/books/prealgebra-2e/pages/9-5-solve-geometry-applications-circles-and-irregular-figures, retrieved 2026-10-01); NIST SP 811: 1 in = 0.0254 m
- Skirt Half circle, Waist 27.56 in, Skirt length 23.62 in, Hem and seam allowance (optional) 1.181 in gives Waist radius 8.772 in, Hem circumference 101.8 in, Outer radius 33.58 in, Fabric rectangle, width 67.15 in, Fabric rectangle, length 33.58 in.Source: Circumference of a circle C = 2πr (OpenStax Prealgebra 2e, section 9.5, https://openstax.org/books/prealgebra-2e/pages/9-5-solve-geometry-applications-circles-and-irregular-figures)
- Skirt Quarter circle, Waist 30 in, Skirt length 20 in gives Waist radius 19.1 in, Outer radius 39.1 in, Hem circumference 61.42 in.Source: Circumference of a circle C = 2πr (OpenStax Prealgebra 2e, section 9.5, https://openstax.org/books/prealgebra-2e/pages/9-5-solve-geometry-applications-circles-and-irregular-figures)
How it works
A circle skirt is a ring (or part of a ring) of fabric. Its inner edge goes around the waist, so the inner edge’s length must equal the waist. With f the fraction of a circle (full 1, 3/4 circle 0.75, half 0.5, quarter 0.25):
- Waist radius r = waist ÷ (2π × f)
- Outer radius R = r + skirt length + allowance (the allowance is 0 when left empty)
- Hem circumference = 2π × (r + skirt length) × f, the finished hem edge without the allowance
- Fabric rectangle, the smallest rectangle that holds the pattern in one piece: 2R by 2R for a full or 3/4 circle, 2R wide by R long for a half circle, and R by R for a quarter circle. The calculator gives the width first and the length second.
The waist you type is the finished waist, with any ease you want already added.
Rules
- The waist and the skirt length are more than 0 and at most 5 m (196.85 in); the allowance is from 0 to 1 m.
- Units are converted exactly: 1 in = 2.54 cm, 1 ft = 12 in.
What the calculator shows
Every length is shown to 4 significant figures, rounded half up, in inches for US units and centimetres for Metric. The chart shows how the fabric length changes with the skirt length for your waist.
Worked examples by hand
Full circle, 28-inch waist, 22 inches long. r = 28 ÷ (2π) = 4.456 in. R = 4.456 + 22 = 26.456 in. Hem = 2π × 26.456 = 166.2 in. Fabric: 52.91 in by 52.91 in.
Half circle, 70 cm waist, 60 cm long, 3 cm allowance. r = 70 ÷ π = 22.28 cm. R = 22.28 + 60 + 3 = 85.28 cm. Hem = π × (22.28 + 60) = 258.5 cm. Fabric: 170.6 cm wide by 85.28 cm long.
Quarter circle, 30-inch waist, 20 inches long. r = 30 ÷ (π ÷ 2) = 60 ÷ π = 19.10 in. R = 19.10 + 20 = 39.10 in. Hem = (π ÷ 2) × (60 ÷ π + 20) = 30 + 10π = 61.42 in. Fabric: 39.10 in by 39.10 in.
Other questions people ask
How do I find the waist radius for a circle skirt?
Divide the waist by 2π for a full circle. For a 3/4 circle divide by 2π × 3/4, for a half circle by π, and for a quarter circle by π ÷ 2. A 28-inch waist gives a full-circle radius of 28 ÷ 6.2832 = 4.46 inches.
How much fabric do I need for a full circle skirt?
A square of fabric 2 × the outer radius on each side, where the outer radius is the waist radius plus the skirt length plus any allowance. A 28-inch waist and 22-inch length need a square about 52.9 inches across, wider than most fabric, so many full circles are cut in two half-circle pieces.
What is the difference between a full, half and quarter circle skirt?
The fraction of a circle the pattern covers. A full circle skirt has the most flare and the longest hem; a half circle has half the hem and less flare; a quarter circle is the slimmest and uses the least fabric.
Do I add seam and hem allowance?
Add the hem allowance and the waist seam allowance in the allowance box; the calculator adds them to the outer radius so the fabric is big enough. Some sewists also take the waist seam allowance off the waist radius; the calculator does not.
How do I mark the circles on the fabric?
Fold the fabric so the centre of the circle is at a corner, hold a tape measure there, and mark points at the waist radius and at the outer radius as you swing the tape. Join the points into two curves and cut along them.
Why is my hem uneven after hanging the skirt?
Parts of a circle skirt fall on the bias, which stretches under its own weight. Hang the skirt for a day before hemming, then trim the hem level. The calculator does not include this drop.