---
title: "Flat-felled seam allowace"
---

Controls the amount of seam allowance on flat-felled seams.

The armhole and side seams on the shirt are flat-felled seams, and those require extra seam allowance.
How much is a matter of personal preference, since some people prefer wider flat-felled seams,
while others have a preference for more narrow flat-felled seams.

This option controls the amount of flat-felled seam allowance as a factor of the regular seam allowance.

## Effect of this option on the pattern

![This image shows the effect of this option by superimposing several variants that have a different value for this option](simon_ffsa_sample.svg "Effect of this option on the pattern")