Back to Basics: What is a Power Reserve Indicator Watch?

But First, What is Power Reserve?

Mechanical watches can run on either a hand-wound movement or an automatic movement. While hand-wound movements get their power from the wearer manually turning the winding crown to wind up the mainspring, the mainspring in automatic movements gets automatically wound thanks to the natural motion of one’s wrist.

Regardless of the type of mechanical movement, both hand-wound ones and automatic ones have a power reserve. In a hand-wound watch, the power reserve refers to how long the watch will keep on working until it needs to get manually wound again. On the other hand, in an automatic watch, the power reserve refers to how long a watch will keep working when it’s off the wrist until it runs out of juice.

On most mechanical watches, wearers have to keep track of the power reserve themselves by remembering when was the last time they either hand-wound they watch or when they took the watch off. However, this is not the case with a power reserve indicator watch.

What is a Power Reserve Indicator Watch?

A power reserve indicator watch is one that has a display somewhere on the dial to let the wearer know how much power the watch has left. In short, it takes out the guesswork for the wearer and lets him or her know just long they have until they have to either wind up the watch or place it back on the wrist.

There are some fantastic luxury watches out there equipped with this practical complication. Let’s check out some of our favorite power reserve indicator watches right now at different price points.

Patek Philippe ref. 5051 Moon Phase Power Reserve

Since the famous watch manufacture is known for their exquisite watches and skillful complications, it comes as no surprise that Patek Philippe would offer plenty of watches with power reserve indicators. Case in point is this beautiful Patek Philippe ref. 5051 in rose gold with not just a power reserve indicator on the dial, but also a subdial for the moon phase and a subdial for the running seconds. Dubbed the “Age of the Moon” watch, this Patek Philippe can indicate the exact time of the full moon.

The 35mm gold case is adorned with an intricate hobnail bezel while the Officer Style caseback includes a hinged cover that can be opened to reveal the automatic movement behind the transparent caseback. The famous Caliber 240PS with its mini rotor has a power reserve of 48 hours–which is, of course, tracked on the dial via the power reserve indicator at the 10 and 11 o’clock position.

Breguet Classique Réveil du Tsar 5707

Yet another renowned Swiss watch brand famous for their complications is Breguet–a company founded by Abraham-Louis Breguet, who many consider the grandfather of modern horology. While Breguet is known for inventing the tourbillon mechanism, today we’re highlighting one of their incredible alarm watches.

In addition to the alarm function, the Breguet Classique Le Réveil du Tsar 5705 also a host of other complications on the silver guilloche dial. There’s the running seconds subdial, the date window, the second time zone indicator, and a power reserve indicator. On the dial there are also the signature Breguet style blue ceneter hands and the classic black Roman numerals. While this is certainly a lot of information packed into a 39mm yellow gold case, in true Breguet fashion, the dial is well balanced and legible. Powering the impressive timepiece is the self-winding Caliber 519F with 45 hours of power reserve.

IWC Big Pilot IW500402

Moving away from elegant dress watches, now we have a sportier example of a power reserve indicator watch from IWC. Rather than the more common stainless steel versions, this IWC Big Pilot ref. IW500402 is actually crafted in 18k white gold. The very large 46mm white gold case with the familiar oversized onion-style crown houses the customary aviation-inspired dial of the Big Pilot series.

On that sunburst gray dial, we see the signature oversized Arabic numerals in white gold, the white gold center hands, the triangle at 12 o’clock, and the minute track running around the periphery. Plus, along with the date window at 6 o’clock, there is also a subdial at 3 o’clock to keep track of the 7-day power reserve! That’s right, seven full days of power reserve is what you get with this watch thanks to the in-house IWC Caliber 51111 automatic movement.

Zenith Defy Classic Open El Primero 03.0526.4021

For a chronograph version of the power reserve indicator watch, we look to the famous Zenith El Primero chronograph. The Zenith El Primero caliber is a legend in the luxury watch space, an automatic chronograph movement so respected that even Rolex used is as a base for earlier versions of their automatic Daytona watches.

Fashioned from stainless steel, the Zenith Defy Classic Open El Primero ref. 03.0526.4021 includes a 46.5mm case furnished with screw-down chronograph pushers flanking the winding crown. The black guilloché dial is home to an opening at 10 o’clock to reveal the part of the of 4021 SC El Primero caliber, a 30-minute counter at 3 o’clock, a small seconds-hand at 9 o’clock, and finally, a power reserve indicator sweeping across the bottom of the dial fom 5 to 7 o’clock.

Whether you opt for a dressier version or a sporty one, a power reserve indicator watch is a great timepiece to have in any watch collection. A practical function that also shows off the skills of the watchmakers who built it, it’s a subtle reminder of the wonderfully intricate and complex movement that powers the watch on your arm.