🕰️ Watch Power Reserve Calculator
Estimate remaining power reserve and running time for mechanical, automatic, and quartz watches. Understand what affects power reserve and how to manage your collection.
Total power reserve (hours)
Hours since last full wind
Watch type
Wearing habits (automatic only)
Temperature
Power Reserve Status
Empty

Famous Movements & Power Reserves

ETA 2824-2

Workhorse Swiss automatic. 38 hours power reserve. Found in thousands of watch models.

ETA 2892-A2

Slim, high-quality Swiss automatic. 46 hours. Used in many prestige OEM watches.

Rolex Cal. 3235

Rolex's proprietary movement. 70 hours. Found in Datejust, Day-Date.

Patek Philippe Cal. 324

High-end Swiss automatic. 45–72 hours. Found in Nautilus and Calatrava.

Omega Co-Axial 8500

In-house Omega movement. 60–80 hours. Master Chronometer certified.

Jaeger-LeCoultre 939A

5-day (120 hour) power reserve. Found in JLC Master Ultra Thin Perpetual.

A. Lange & Söhne 71.3

8-day (192 hour) power reserve indicator. Saxonia Outsize Date.

Quartz (standard)

1–3 year battery life (typical). Roughly 8,760–26,280 hours on a single battery.

🌀 How automatic winding works: The rotor (a weighted semicircle) spins with arm movement, winding the mainspring via a series of gears. An efficient rotor fully winds the watch in about 6–8 hours of normal arm movement. A watch winder simulates this when the watch is not being worn.

🌡️ Temperature effects: Cold temperatures thicken lubricant oils, increasing friction and reducing accuracy + power efficiency. Heat reduces lubricant viscosity. Extreme temperatures (below -10°C or above 40°C) can permanently affect lubricants — avoid leaving watches in cars in summer or winter.

🔋 When to service: Mechanical watches should be serviced every 3–7 years. Signs it's needed: losing/gaining more than ±15 seconds/day, stops unexpectedly despite power, crown feels different, visible moisture under crystal. Regular servicing prevents costly damage from worn lubricants.