Why does my automatic watch not keep accurate time? The accuracy of TAG Heuer watches depends on several factors, including the type of movement and conditions of use. The following list shows TAG Heuer average tolerance given by the Swiss movement suppliers (based on normal conditions, and full power reserve for automatics): Quartz movement: between -1 and +11 seconds per month Standard automatic: between -5 and +20 seconds per day Chronometer: between -4 and +6 seconds per day https://faq.tagheuer.com/articles/en_US/FAQ/What-is-an-automatic-movement/?l=en_US&c=Watches%253AAll_Watches&fs=Search&pn=1