Metric ↔ Imperial Sewing Conversions
Convert any sewing measurement between inches, centimeters, yards, and meters.
Common fractional inches → metric
| Inches | Centimeters | Millimeters |
|---|---|---|
| 1/8 in | 0.32 cm | 3.2 mm |
| 1/4 in | 0.64 cm | 6.4 mm |
| 3/8 in | 0.95 cm | 9.5 mm |
| 1/2 in | 1.27 cm | 12.7 mm |
| 5/8 in | 1.59 cm | 15.9 mm |
| 3/4 in | 1.91 cm | 19.1 mm |
| 7/8 in | 2.22 cm | 22.2 mm |
| 1 in | 2.54 cm | 25.4 mm |
The conversion factors used here
1 inch = 2.54 cm exactly, and 1 yard = 0.9144 m exactly — both are internationally defined conversion factors, not approximations, so these numbers are as precise as your measuring tools allow.
Why the fraction chart matters
Sewing measurements are almost always given in eighths of an inch (1/4", 3/8", 5/8") rather than decimals, but most rulers marked in metric only show whole millimeters or centimeters. Rounding 5/8" to "1.6 cm" instead of the precise 1.59 cm won't matter for a hem, but it compounds across multiple seams on a fitted garment — use the more precise millimeter figure when a pattern needs to match exactly.