What this calculator does
A circle skirt is one of the simplest garments to draft: two circles drawn from the same point. The inner circle is your waist and the outer one is the hem. The only real calculation is the waist radius, which depends on how much of a circle you are making. This calculator works it out, adds seam and hem allowances, and lays the pieces on your fabric width to estimate yardage.
How to use it
- Measure your natural waist (or wherever the skirt will sit) and the length from there to the hem.
- Choose full, half or quarter circle and your fabric width.
- Fold the fabric, then from the folded corner mark the waist radius and the hem radius with a tape measure, swinging it in an arc.
- Cut both arcs. A full circle on narrow fabric is cut as two half circles and seamed.
The math
full circle: waist radius = waist ÷ 2π
half circle: waist radius = waist ÷ π
quarter circle: waist radius = 2 × waist ÷ π
hem radius = waist radius + length + hem allowance
For a 28 inch waist and 22 inch full skirt: the waist radius is 28 ÷ 6.283 = 4.46 inches, cut at 3 7/8 inches with a ⅝ inch seam allowance. The hem radius is 27 1/2 inches. The circle is 54 7/8 inches across, which just fits 58 inch fabric, so the layout is one full circle and you need 1 5/8 yards. On 45 inch fabric it would have to be cut as two half circles.
Fabric tips
- Wide fabric (58 to 60 inches) often fits a full circle in two pieces for a knee-length skirt.
- Avoid one-way prints for full circles: the print will be upside down at the back.
- Lightweight cottons, rayon and crepe swing well. Stiff fabrics stand away from the body.
Add a waistband. These numbers are for the skirt only. A waistband is a rectangle your waist measurement plus ease and overlap long, and twice its finished height plus seam allowances wide.
Questions people ask
What is the difference between full, half and quarter circle skirts?
A full circle skirt makes a complete ring of fabric and has the most swing. A half circle uses half as much fabric and drapes more softly. A quarter circle is a gentle A-line and uses the least fabric.
Why is the waist radius so small?
The waist measurement is the circumference of the inner circle, and radius = circumference ÷ 2π for a full circle. A 28 inch waist only needs a radius of about 4½ inches.
Why subtract the seam allowance from the waist radius?
Cutting the waist circle smaller by the seam allowance means the seam line, not the cut edge, matches your waist. The calculator shows both.
Should I let a circle skirt hang before hemming?
Yes. Parts of a circle skirt are cut on the bias and stretch. Hang it for 24 hours, then level the hem before you sew it.