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What are Watch Subdials? A Closer Look at the Mini-Dials

What are Watch Subdials? A Closer Look at the Mini-Dials

Watch subdials are part of the dial but smaller to display different functions, such as the complications or running seconds. Explore here!
Mar 27, 2024

The watchmaking industry is a world full of terminology that sometimes can be confusing for a newbie, especially if the term doesn’t describe anything about how it looks. Worry not, some others are also self-explanatory, such as the watch subdials. As the name suggests, it is part of the dial but is smaller to display various functions. 

As you are here, we believe that you still want to know more about what watch subdials are and their functions. As a glimpse of information, watch subdials can serve different functions depending on the feature the watch wants to offer. It’s quite common to display calendars or seconds display in a chronograph. 

There are many things you can explore about watch subdials from the function to designs. This article would further scrutinize all information you need about this part of the watch.   

What’s More to Know About Watch Subdials?

Watch subdials are smaller dials placed on the dial to serve certain functions or give additional information aside from just the time. It is something you definitely spot in a chronograph as every chronograph would feature subdials. 

In this case, the subdials are also called registers that could measure the elapsed time or keep track of the total minutes and hours on the chronograph. 

When it comes to appearance, you can find various designs for watch subdials. Commonly, it takes form as a round but is also frequent in squares. Most watchmakers would take a form that echoes the cushion shape. The number of subdials on a watch also varies depending on the function and complication of the watch.

Some might have only one, two, three, and even four subdials that come in various layouts. That said, you can expect to collect watches with subdials in various appearances. For example, this Hamilton American Classic Intra-Matic Chronograph H Black has two sub-dials placed at the 3 and 6 o’clock position and, thus, referred to as a bi-compax layout. 

Hamilton American Classic Intra-Matic Chronograph H Black

In addition, a timepiece with three subdials is also known as a tri-compax. It is important to note that not all subdials display a watch complication. Let’s take Seiko Prospex Speedtimer Chronograph White as an example. It features three subdials at the 3, 6, and 9 o’clock positions.

Seiko Prospex Speedtimer Chronograph White

The one at 3 o’clock displays the 24-hour time, the 9 o’clock subdial shows the running seconds, and the 6 o’clock is dedicated to dual functions: a 60-minute elapsed time counter and a power reserve indicator. The running seconds are not a complication.

Read more: Through the Looking Glass: The Different Types of Dials Out There

Common Types of Watch Subdials

As mentioned before, there are several types of subdials that are common in mechanical watches. Below are some of them along with each function.


Watch subdials are part of the chronograph as it needs additional dials to display the stopwatch measurement. A chronograph watch is also known as a stopwatch that allows the wearer to measure the amount of time that elapses between its activation and deactivation.

Some chronograph is equipped with pushers beside the crown to stop or start the chronograph. That way, you can easily use the stopwatch function without being afraid of changing the time.

In brief, the subdials in a chronograph aim to provide better legibility to tell the time. It separates the display for seconds, minutes, and hours separately. 

GMT Watch Subdials

As you can expect from the name, GMT subdial display the second time zone. It was first introduced and became popular when air travel was growing in the 1950s. It aims to help pilots or travelers to indicate different time zones in one timepiece. 

Although it’s common to use a bezel or GMT hand to indicate the second time zone, some also use a subdial. It somehow can help people who are just new to GMT watches better understand how to read the second time.

Power Reserve Indicator

For mechanical watch enthusiasts, knowing the remaining power is indeed crucial to avoid the watch stops working. This is why a power reserve indicator comes as a savior. The subdial will display how much-stored energy from the mainspring is left before it stops running. 

Mido Multifort Power Reserve Blue Ref. M038.424.11.041.00

Moonphase Subdial

Last but not least, subdials are also common in a timepiece with a moonphase complication. It is a timepiece that provides information about the lunar cycle for 29,5 days. 

Ball Watch Co. Trainmaster Moon Phase Black - Leather - Ref. NM3082D-LLJ-BK

The subdial displays the current moonphase, such as the new moon, crescent, and full moon through an aperture. 


A Subdial is a small dial but also part of the whole construction of a timepiece and serves a significant function. From the explanation above, we’ve known that there are several types of watch subdials in the market. Not only that it comes in different functions but also designs and layouts.

You might also like: How to Choose Watch Dial Color That Suits You Well

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