Seam Allowance, Dart & Buttonhole Calculator

Add seam allowance to a pattern piece in inches or centimeters, work out dart intake, and size buttonholes for any button.

Switch between inches and yards or centimeters and meters with the units button. Results update as you type. When you know how much you need, order your fabric by the meter: one meter is 39.37 inches, about 9% more than a yard.