Pattern cutting · cut size

Seam Allowance Calculator

Convert a finished rectangular panel size into cut dimensions by adding seam allowance on all four edges.

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Calculate your requirement

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Enter the finished panel and seam allowance.

Results will appear here.

Before you cut: Does not include hems, facings, turn-of-cloth, corners, curves, notches, or asymmetric allowances. Important production quantities should be independently verified.

01 / METHOD

How to use this calculator

  1. Enter the finished dimensions inside the seam line.
  2. Enter the allowance applied to each of the four edges.
  3. Set the number of identical rectangular panels.
  4. Use the cut dimensions in a layout calculator if yardage is required.

02 / APPLICATION

Useful for

  • Cushion panels, flags, and simple covers
  • Pattern drafting checks
  • Cut-ticket preparation

03 / BOUNDARIES

Assumptions and limitations

What the estimate assumes

  • One equal allowance applies to every edge.
  • Panels are rectangular and quantity is a whole number.

What it does not model

  • Does not include hems, facings, turn-of-cloth, corners, curves, notches, or asymmetric allowances.
  • Total cut area is not a fabric yardage requirement.

04 / NOTES

Frequently asked questions

Why is the allowance added twice per dimension?

A rectangle has two opposite edges in each direction, so one allowance is added at both ends.

Does total area include cutting waste?

No. It is the exact area of the rectangular cut panels only.