I have a Rolex Submariner Date and I've honestly never checked, but I will. I guess it's always been accurate enough and I've never been enticed to actually measure. I've owned the watch for almost 13 years [from new] and it's never been serviced [I know, naughty boy - the cost always scared me away]. It's had the snot kicked out of it too, which is why I bought it in the first place.