Test the real power reserve of your automatic or mechanical watch. Start the timer after a full wind, come back when the watch stops, and compare the actual running time with the manufacturer’s claimed figure.
Common values: Seiko 5 ≈ 41h · ETA 2824 ≈ 38–42h · Rolex ≈ 70h · Grand Seiko ≈ 72h
1. Fully wind the watch (or wear it until the power reserve is topped up).
2. Set the time accurately and start this timer at the same moment.
3. Leave the watch in a consistent position (dial up is common).
4. When the watch stops, come back and press “Watch Stopped – Finish Test”.
5. The tool will show the real running time and compare it with the claimed power reserve.
For the most reliable result, avoid wearing the watch during the test so the rotor does not add extra energy.
Manufacturers measure power reserve under ideal laboratory conditions. In real life the result can be shorter because of:
• Position of the watch (dial up, crown down, etc.)
• Age and condition of the lubricants
• Amplitude and regulation of the movement
• Temperature
• How fully the mainspring was wound
What is a good real-world power reserve? If your watch achieves 85–100% of the claimed figure it is considered healthy. Significantly less may indicate the movement needs service.
Should I wear the watch during the test? For a pure power-reserve measurement, no. Wearing it allows the rotor to add energy and will make the result longer than a true static power reserve.
How long should I fully wind the watch? On most automatic watches, 30–40 turns of the crown after the watch has stopped is enough to reach full power reserve. Stop when you feel resistance.
Is the data saved? The current test is saved in your browser so you can close the page and return later. Once you finish or reset, the timer starts fresh.