Watch GlossarySub-dial

What Is A Sub-Dial On A Watch?

A sub-dial is a miniature or auxiliary dial located on the watch dial, reserved for functions beyond the primary timekeeping hours and minutes that the central hands provide. Also called counters or registers, these are found in mechanical and special watches like calendars, chronographs, and GMT watches. Sub-dials are always present on chronograph watches. They improve the overall reading of elapsed time by breaking down the seconds, minutes, and hours separately.

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Types Of Sub-dials

Chronograph sub-dials (Hours, minutes and/or seconds)

The keeping of chronograph hours, minutes, and running seconds, are indicated on separate sub-dials in chronograph watches as a bi-compax and tri-compax setup. Sub-dials improve the overall reading of elapsed time by breaking down the minutes, and hours separately. While the chronograph counters are most commonly 30-minute and 12-hour counters, a third sub-dia on sub-dial on a chornograph watch dial displays the running seconds of the primary timekeeping of the watch.

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Date and/or day sub-dials, for calendar watches

In the absence of a date window certain date watches have an analogue date display, where there’s often a sub-dial with a hand that goes from the 1st to the 31st of the month. In perpetual calendar watches, particularly, there might be similar sub-dials for analogue displays of the day, month and even leap years.

The Bovet Récital 27 features two sub-dials for three time zones, encircling day/night indications, one moon phase, and power reserve indicator

Featuring a figure ‘8’ window sprinkled with stars, the lower section of the hemispheric precision moon phase is applied with Super-LumiNova and decorated with craters

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Power reserve indicator

Usually located as a fan-shaped insert that displays the amount of stored energy left in the mainspring before the watch stops running and needs winding. The power reserve display can also be in a standard cirular sub-dial.

Moon Phase sub-dial

This counter showcases the pictorial depiction of the changing stages of the moon—new, waxing, crescent, or full moon—in real time.