Circle Skirt Calculator

Enter your waist, the finished length and the type of circle skirt. The calculator gives the two radii to mark from one centre point, with seam and hem allowances included, and how much fabric a one-piece cut needs.

  • Sewing & quilting
  • Formula and worked example
  • Runs in your browser

1Measurements

Units

Where the skirt will sit, measured snugly.

2Allowances and fabric

Waist cutting radius

Hem cutting radius

Full result

The formula

Waist radius = waist ÷ (2π × fraction of a circle: 1, 3/4, 1/2 or 1/4)
Waist cutting radius = waist radius − seam allowance
Hem cutting radius = waist radius + finished length + hem allowance
A full or three-quarter circle needs a square of side 2 × hem radius, a half circle 2 × hem radius by one hem radius, and a quarter circle one hem radius square

Worked example. a 70 cm waist full circle skirt 60 cm long has a waist radius of 11.1 cm and a hem cutting radius of 73.6 cm, so it fits on 150 cm fabric in one 1.5 m piece.

How to use it

  1. Measure your waist where the skirt will sit, snugly but not tight, and decide on the finished length.
  2. Choose the skirt type. A full circle has the most swing; half and quarter circles use far less fabric and hang closer to the body.
  3. Enter your waist seam allowance and hem allowance. A narrow rolled hem needs as little as 1/4 in (6 mm).
  4. Mark the waist cutting radius and the hem cutting radius from the same point on folded fabric, then cut along both curves.

Questions

Why is the waist cut smaller than the waist radius?

The seam allowance sits inside the waist curve, so the cutting line is one seam allowance closer to the centre. When you sew the waistband on at the allowance, the stitching line is exactly your waist measurement.

My skirt is wider than my fabric. What now?

Cut it in panels: two half circles for a full skirt, or quarter-circle panels, each with a side-seam allowance added. The calculator shows a dash for fabric when one piece will not fit.

Why does the hem look uneven after a day?

Parts of a circle skirt hang on the bias and stretch under their own weight. Hang the finished skirt for 24 hours before levelling and hemming.