Seam Allowances and Hems

Part 1: More Seam Allowance Is Not Always Better

Many dressmakers believe that a very wide seam allowance is better. The idea is that extra fabric can be used to alter the garment later. That sounds sensible but it does not work that way in practice.

If you add more than 1 inch to a curved side seam when working with woven fabric, the allowance may not lie smoothly. You may have to clip it to allow the curve to actually curve.

Once you clip that seam allowance, you have defeated the reason for the wider seam. By clipping the seam allowance, you damage the edge, and enlarging the garment exposes that damage. This means there can be no expansion of the garment.

A 1-inch allowance is usually enough for a curved side seam. It can follow the curve without clipping and still gives useful room for fitting and future adjustment.

As a practical guide, every additional ½ inch available at the side seams can give approximately one more garment size. The exact increase will depend on the sizing system and the garment design.

Extra seam allowance also uses extra fabric. On one garment, the difference may appear small. When you cut many garments, that unnecessary width becomes a great deal of wasted fabric.

The goal is not to add the widest seam allowance possible. The goal is to add enough for sewing, fitting and future alteration—without creating bulk or waste.