How accurate is a watch?

A typical automatic watch runs within roughly −10 to +30 seconds a day; a well-regulated movement stays within a few seconds. That is normal — and it is why you set a mechanical watch now and then. A quartz watch, by comparison, runs within about 15 seconds a month.

Chronometer is a title, not a function: it is awarded by the Swiss testing institute COSC to movements that, over 15 days of testing, stay within −4/+6 seconds a day in several positions and temperatures. It should not be confused with a chronograph, which is a stopwatch built into the watch. If your watch suddenly runs very wrong, magnetism is the most common cause — see accuracy and service if it is one of ours.

If you have a question about a particular watch, ask Nord, our assistant, at the bottom right — or write to us.