👗 Circle Skirt Calculator
Enter your waist measurement and desired length to find the pattern radius for a circle skirt.
How circle skirt patterns work
A circle skirt is cut from a ring of fabric: a small circle is cut out of the middle for the waist, and the outer edge becomes the hem. Getting the waist circle radius right is the key measurement for the pattern to fit properly.
The formula
Since Circumference = 2πr, the waist radius is found by rearranging to Radius = Waist Measurement ÷ (2π) for a full circle skirt (or ÷ π for a half circle, since it uses half the fabric ring). The outer hem radius is then Waist Radius + Skirt Length, which tells you how big a fabric square you need per skirt panel.
This calculator assumes a stretch-free woven fabric and a simple flat pattern — add extra for seam allowance and account for fabric stretch on the bias if using knit fabric. For general sewing planning purposes.