The honest answer is more than you think, and running out mid-seam is a needless annoyance.
Rough guidance for a sewing machine. A simple garment — a shirt, a skirt — typically uses 150 to 250 metres including seams, finishing and topstitching. A lined jacket can use several hundred. A 100 m spool is a starter quantity, not a project quantity.
Overlockers are the real consumers. Four threads run simultaneously and the machine sews fast, so an overlocker gets through cones at four times the rate a sewing machine gets through spools. This is why overlocker thread is sold on 1,000 m and 2,000 m cones rather than spools.
Buy larger spools of the colours you actually use. Black, white, navy, grey. For occasional colours a 100 m spool is fine.
One practical rule. Never start a long seam on a nearly empty bobbin. Wind a fresh one — running out halfway means an unavoidable join, which is a weak point and shows on topstitching.
And buy the thread with the fabric, matching in daylight. Thread reads darker on the spool than it sews, so if you are between two shades, take the lighter one.
Questions people actually ask
Should I match thread exactly?
Close is fine for construction seams. For visible topstitching, match carefully or contrast deliberately — a near-miss looks like a mistake.
Does thread go off?
Cotton degrades with age and humidity; polyester lasts almost indefinitely. Test old thread by pulling a length between your hands.
Last reviewed 2026-08-11