Chronometer specs

[MikeHendrick1978]

What is typical time to lose or gain for a watch that is chronometer certified? I have a Ball watch that is a Chronometer certified and it seems to either lose or gain over 5 seconds over the course of a day. if I don't wear it for three days and I put it on a winder it loses a lot more than that.

[enjoythemusic]

Accuracy of a Master Chronometer is independently certified at between 0 and +5 seconds per day variance, which ensures the watch will never lose time and the certified accuracy is superior to that of the general COSC-certified chronometers which are between -4 and +6 seconds per day.

[MikeHendrick1978]

thank you so much....so should I be concerned about the time I am losing or gaining or is this normal?

[enjoythemusic]

Hmm... a 10-second swing is a bit larger than normal imho. How old is it / how long have you had it? Do you wear it 24/7 or ???

[MikeHendrick1978]

I have had it since I bought it new in September 2021. I wear it maybe two or three days a week if that and when it is not worn, I put it in a watch winder.

[Tools]

Originally Posted by MikeHendrick1978

What is typical time to lose or gain for a watch that is chronometer certified? I have a Ball watch that is a Chronometer certified and it seems to either lose or gain over 5 seconds over the course of a day. if I don't wear it for three days and I put it on a winder it loses a lot more than that.

A Swiss watch is tested by COSC under severe conditions, and it must maintain a -4/+6 swing from the reference setting in order to pass. Yes, that is a 10 second swing in order to pass the Chronometer Test.

It is never tested again. Some think that it should run -4/+6 from their Atomic clock, but that isn't what COSC is or says. None of us truly expect our watch to ever see a 10 second swing on any given day.

If you are not happy with how your watch performs, take it in for regulation or a service. Most modern watches can perform within a few seconds per day.

[MikeHendrick1978]

thank you so much....I have reached out to the AD that sold it to me to find out how I could get it serviced under warranty as it still is in that period.

[WatchEater666]

Originally Posted by Tools

A Swiss watch is tested by COSC under severe conditions, and it must maintain a -4/+6 swing from the reference setting in order to pass. Yes, that is a 10 second swing in order to pass the Chronometer Test.

It is never tested again. Some think that it should run -4/+6 from their Atomic clock, but that isn't what COSC is or says. None of us truly expect our watch to ever see a 10 second swing on any given day.

If you are not happy with how your watch performs, take it in for regulation or a service. Most modern watches can perform within a few seconds per day.

Agreed. I have found my mass produced watches like Rolex, Hublot, UN, etc to hold time better than complicated haute pieces FWIW.