Accuracy (Daily Deviation)
Accuracy describes how far a watch drifts from true time, given in seconds per day. A quartz watch drifts a few seconds a month, while a good mechanical drifts a few seconds a day. It is a property of the movement type, not a fault.
At a glance
- Unit
- Seconds per day
- Typical quartz drift
- A few seconds a month
- Typical mechanical drift
- A few seconds a day
Accuracy is not a measure of a flaw, as many assume, but a property that shows how the movement works. Drift is expressed in seconds per day, and the movement type sets the size of that number from the start.
What determines drift
The two main builds behave very differently:
- Quartz: drifts only a few seconds a month, the most accurate choice for daily wear
- Mechanical: even a good example drifts a few seconds a day, which is expected behavior
You can read where that gap comes from in our quartz watch and mechanical watch entries.
Reducing drift
The drift of a mechanical watch is not fixed, and resting position affects it. Letting the watch rest overnight in a particular position can offset some of the daily drift. This idea sits at the heart of our standards category, where we collect measurement terms.
For options that keep good daily time, read our guide to the best Japanese watches.
Examples
If daily accuracy matters most, a quartz watch is the most reliable choice, drifting only a few seconds a month.
A good mechanical watch is expected to drift a few seconds a day, which is normal rather than a fault.
View this watch
Comparison
The daily drift of quartz and mechanical movements differs sharply.
| Option A | Option B | Notes |
|---|---|---|
| Quartz movement | Mechanical movement | Quartz drifts a few seconds a month; a good mechanical drifts a few seconds a day. |
Related terms
Watches that show this
Frequently asked questions
How is accuracy measured in seconds per day?
Accuracy describes how far a watch drifts from true time, given in seconds per day. A quartz watch drifts a few seconds a month, while a good mechanical drifts a few seconds a day.
Is it a fault if my mechanical watch drifts a few seconds each day?
No, that is not a fault. Daily drift is a property of the movement type, and a few seconds a day is expected behavior on a good mechanical watch.
Can I reduce a mechanical watch's daily drift?
Somewhat, yes. Resting positions can reduce mechanical drift, so letting the watch rest overnight in a particular position can offset some of the daily drift.