Seam Allowance Calculator
Calculate fabric dimensions including seam allowances
About this calculator
The Seam Allowance Calculator helps sewers and quilters determine the total fabric dimensions needed for their projects by automatically adding seam allowances to finished measurements. This essential tool eliminates guesswork and prevents costly fabric shortages by calculating precise cutting dimensions. Whether you're working on garments, quilts, or home decor projects, this calculator ensures you purchase and cut the correct amount of fabric while accounting for seams, hems, and construction requirements.
How to use
Enter your desired finished dimensions for length and width, then specify your seam allowance width (typically ¼ inch to ⅝ inch). The calculator will instantly display the total fabric dimensions you need to cut, including seam allowances on all sides. Use these calculated measurements when cutting your fabric pieces.
Frequently asked questions
What is a standard seam allowance?
Standard seam allowances are ⅝ inch for garments, ¼ inch for quilting, and ½ inch for home decor projects.
Do I add seam allowance to all sides?
Yes, seam allowances are typically added to all edges that will be sewn, doubling the allowance for total dimensions.
How do I calculate seam allowance for curved seams?
Use the same measurements as straight seams, but consider adding slightly more for curves that require clipping or notching.