Watch bench
The exact time to set your watch by, a log of how well it keeps time, and a check of how a case size suits your wrist.
Setting a watch to the second
The clock in a phone or computer is usually right to within a second, but not always: it can drift by several seconds between automatic corrections. This page compares your device’s clock with the time on the server that sent the page and shows the corrected time, along with how far out your device is. To set a watch, pull the crown when its seconds hand reaches twelve, set the minute hand to the next minute, and push the crown back in on the long pip.
How accurate should a watch be?
| Type of watch | Typical gain or loss |
|---|---|
| Quartz | About 15 seconds a month, or half a second a day |
| Certified chronometer (mechanical) | Between 4 seconds slow and 6 seconds fast a day |
| Modern mechanical | Within 10 to 15 seconds a day |
| Older or basic mechanical | Up to 30 seconds a day |
A mechanical watch that suddenly runs minutes fast has usually been magnetised, which a watchmaker can fix in moments. One that slowly gets worse over years is due for a service.
Measuring your own watch
Take a reading on the Accuracy tab: tap the button at the moment your watch’s seconds hand passes twelve. Do the same a day later. The difference between the two readings is how much the watch gained or lost. More readings over a week give a steadier figure, and mechanical watches run at slightly different rates on the wrist, lying flat and resting on their side, so note the position if you want to find the best way to leave it overnight.
Common questions
Will a watch fit my wrist? The measure that matters most is lug to lug, the length from the tip of the top lugs to the tip of the bottom ones. If that is longer than your wrist is wide, the watch overhangs and the strap cannot wrap properly. The size tab draws the watch on a wrist of your size.
How is the moon phase worked out? From the average length of the lunar month, 29.53 days, counted from a known new moon. It is right to within a few hours, which is closer than a moon-phase watch can be set.
Why does it say it is using my device’s clock? The time check needs to reach the site. If you are offline it falls back to your device’s own clock and tells you so.