Sewing: The extra cloth between the cut edge of a piece of fabric and the stitch line. The standard seam allowance is 5/8" (1.5 cm) for garments, and 1/4" for quilting.
The purpose of the seam allowance is to protect the seam from any unravelling the cut fabric edge may undergo in the lifetime of the garment. It also gives space for topstitching or slight adjustments in garment size.
Smaller than standard seam allowances may turn up on closely fitted pieces, doll clothing, or items to be sewn on a serger. If you're short of fabric and tempted to skimp on seam allowance, the following considerations apply.
- Use pinking shears to reduce unravelling at the cut edge
- Don't use small seam allowances on high-stress seams such as bodices or armholes
- If the fabric is coarsely woven, use the full allowance, or don't use it for the project. There is no point putting a lot of time into sewing something only for it to unravel straight off.
Most sewing machines have a mark 5/8" from the needle position to align the cut edge while sewing. A 1/4" wide presser foot is available to help quilters keep their seams in the right place.
The seam allowance on a pattern piece is indicated by a dashed line:
__________ cut line
|----------| seam allowance
| pattern |
| piece |