Accuracy
How accurate are quartz watches compared to mechanical watches?
Quartz watches are dramatically more accurate: a typical quartz movement drifts around ±15 seconds per month, while even a COSC-certified mechanical chronometer — the industry accuracy standard — is only guaranteed to −4 to +6 seconds per day. That is a gap of one to two orders of magnitude in quartz's favor.
Why the gap exists
Quartz timekeeping relies on a crystal vibrating at a fixed 32,768 Hz, an electronically stable reference largely unaffected by position or gravity. Mechanical timekeeping relies on a balance wheel oscillating under a hairspring, which is sensitive to temperature, position, magnetism, and how evenly the mainspring delivers torque — all of which introduce small daily variation that never fully disappears, certified or not.
COSC certification (−4/+6 sec/day average, tested across positions and temperatures) is the industry's accuracy bar for "very good" mechanical watches, and stricter house standards exist — Rolex's Superlative Chronometer (−2/+2 sec/day) and Omega's METAS Master Chronometer (0/+5 sec/day) — but none approach quartz-level stability.
Does the gap matter in practice?
For most owners, no — a mechanical watch drifting a few seconds a day just gets reset periodically, which is a minor ritual rather than an inconvenience. The accuracy gap is real and large on paper, but people choose mechanical watches for engineering and feel, not for timekeeping precision, which is exactly why quartz and mechanical continue to coexist rather than one replacing the other.
Frequently Asked Questions
Is a $50 quartz watch more accurate than a $5,000 mechanical watch?
Yes, in raw timekeeping terms. Even inexpensive quartz movements outperform high-end mechanical chronometers on accuracy — price and accuracy are not linked for mechanical watches.
What is considered good accuracy for a mechanical watch?
COSC certification (−4/+6 sec/day) is the recognized bar; house standards like Rolex's Superlative Chronometer (−2/+2 sec/day) go tighter still, but none match quartz-level stability.
Why do people buy mechanical watches if quartz is more accurate?
For the craftsmanship, the visible mechanical movement, heritage, and the fact that a well-serviced mechanical watch can run for generations — accuracy is simply not the reason people choose them.