Sewing Measurement Converter

Sewing patterns in the US use fractional inches (⅛, ¼, ⅜, ½, ⅝, ¾, ⅞). The converter shows the nearest ⅛" fraction alongside the decimal. When measuring, round to the nearest ⅛" — that's the precision most sewing requires.

US fabric is sold by the yard (36"). European and international fabric is sold by the meter (~39.4"). If a US pattern says "3 yards" and you're buying in meters, you need about 2.75 meters. If a European pattern says "2.5 meters" and you're buying in yards, you need about 2.75 yards.

A handful of numbers come up constantly once you start working across US and European patterns. These are the ones worth knowing by heart:

Note that 5/8 in is not exactly 1.5 cm — it is 1.59 cm. Pattern companies round it, and that rounding is deliberate: a 0.09 cm difference is invisible on a single seam, and a round metric number is far easier to sew accurately than a fractional one. The same applies to 3/8 in and 1 cm.

When a pattern gives yardage in one system and your shop sells in the other, always round up to the next quarter unit. A conversion that lands at 2.29 m should be bought as 2.5 m, not 2.25 m — fabric shops cut generously but not precisely, and pre-washing will shrink what you bought.

Check the bolt width before converting yardage at all. Pattern yardage is quoted for a specific width, so a requirement of 3 yards at 45 in is roughly 2.25 yards at 60 in. Converting the number without converting for the width is the most common way to end up short.

For directional prints, napped fabrics like velvet and corduroy, or anything with a one-way design, add roughly 15 percent on top of whatever the conversion gives you. All pieces must be cut facing the same direction, which wastes more fabric than a standard layout.

The most reliable habit is to pick a system at the start of a project and stay in it. Converting back and forth mid-project compounds rounding error: three conversions at 1/16 in each can shift a seamline by nearly 1/4 in, which is enough to throw off a collar or a set-in sleeve.

If your pattern is metric and your rulers are imperial, it is usually easier to buy a metric ruler than to convert every measurement. Sewing measurement is comparative work — you are matching one seam to another far more often than you are hitting an absolute number, and a single set of units keeps those comparisons honest.