Track the daily rate (seconds per day) of multiple mechanical watches over time. Log measurements, compare against COSC standards, and keep a private long-term history — all stored only on your device.
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COSC Chronometer: −4 to +6 seconds per day
Good mechanical: −10 to +20 s/d
Excellent: −4 to +6 s/d
Quartz: typically ±1 to ±3 s/d
How do I measure the rate of my watch? Set your watch to the correct time. After 24 hours (or any known interval) compare it again with an accurate source. Enter the difference in seconds and the hours that passed. The tracker calculates seconds per day.
What is a good accuracy for a mechanical watch? Most modern mechanical watches run between −10 and +20 s/d. COSC-certified chronometers must stay within −4 to +6 s/d.
Is my data private? Yes. Everything is stored in your browser’s localStorage. Nothing is sent to any server.
Can I track several watches? Yes. Add as many watches as you like and log measurements for each one separately.