Seam allowances are the strips of fabric between the seam line (where you stitch) and the cut edge of your fabric. They seem like a minor detail, but getting them right is fundamental to a well-fitting, professionally finished garment.
Standard Seam Allowances
Most commercial sewing patterns include seam allowances, but the standard width varies by country and publisher. Common amounts include 5/8 inch (1.5cm) — standard in US patterns, 1cm — common in European patterns, and 1.5cm — standard in many European and UK patterns. Always check your pattern instructions before cutting.
Why Seam Allowances Matter for Fit
Seam allowances directly affect how a garment fits. If you sew with a 1cm seam when the pattern requires 1.5cm, each seam is 5mm smaller — across a typical top with 10+ seams, that can add up to several centimetres too tight.
Pressing Seam Allowances
How you press seam allowances changes the look and behavior of a garment. Press open for flatness, press to one side for strength, or catch-stitch for invisible finishing on hems.
