How Accurate Is a Quartz Watch? What ±20 Seconds a Month Means
- avantewatches
- Aug 12
- 2 min read
A quartz watch is usually very accurate for everyday wear: a specification of ±20 seconds per month means the movement is designed to gain or lose no more than about 20 seconds over a month under the maker’s stated conditions. It is a useful comparison point before you buy.
What does quartz-watch accuracy mean?
Accuracy is the difference between the displayed time and a dependable reference time. A quartz watch uses an electronic circuit and a vibrating crystal; the regular frequency is divided into seconds. Always compare like with like: seconds per month against seconds per month.
Is ±20 seconds per month good?
Yes. At the maximum rate that is roughly four minutes across a year. MIYOTA specifies ±20 seconds per month, three years of battery life, and day, date, month and moonphase functions for the 6P00. It is practical when you rotate watches and do not want to reset a calendar often.
Why can a quartz watch still drift?
Temperature and daily use
Temperature and daily conditions can affect frequency slightly, which is why a maker’s figure is a tolerance. Set your watch to a reliable reference, record date and time, then compare again after about 30 days. Have unexpected behaviour assessed by a watchmaker, who can also check the battery and seals.
A simple buying framework
Compare the maker’s figure in seconds per month.
Check movement, battery life and service.
Assess crystal, dimensions and fit separately.
The Avanté Lunar Gunmetal lists a 40 mm case, 8.8 mm thickness, sapphire crystal, 5 ATM water resistance and a MIYOTA 6P00 quartz moonphase movement. See the Lunar Gunmetal to judge those details on a live model.
What accuracy does — and does not — tell you about a moonphase watch
Quartz describes the power and timekeeping system; it does not by itself prove that a moon display tracks the waxing and waning moon. Read real moonphase versus day-night indicator. Accuracy is not the same as fit. Use the 40 mm wrist-size guide alongside diameter, lug-to-lug, thickness and bracelet shape.
Frequently asked questions
How many seconds per month can a quartz watch be off?
It depends on the movement; MIYOTA specifies ±20 seconds per month for the 6P00.
Is quartz more accurate than automatic?
Often in daily use, but compare the actual stated tolerance of both movements.
Do I need to wear a quartz watch every day?
No. It normally keeps running off the wrist while its battery has power.
How can I test accuracy at home?
Compare it with the same reliable reference after about 30 days and convert the total difference to seconds per month.
Does a low battery affect accuracy?
Have unexpected behaviour checked professionally; a service visit can also assess the battery and seals.
Conclusion
A quartz watch rated at ±20 seconds per month is accurate enough for most owners to spend more time wearing it than setting it. Then confirm the calibre, battery life and the rest of the product specification.
Sources
Last substantive review: 11 August 2026. FAQ questions are editorially derived from Google Search queries in Wix; Wix does not provide a separate AI-prompt dataset.
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