ChronoLog Watch Accuracy Meter

ChronoLog — Timegrapher, Watch Accuracy Meter & Collection Log

Turn your phone into a timegrapher. ChronoLog listens to your mechanical watch through the microphone and reads its rate in seconds per day — then keeps measuring over days and weeks, on your wrist, so you know how the watch really runs, not just how it ran on the bench.

No subscription. No account. One-time purchase unlocks everything.

AUDIO TIMEGRAPHER
• Rate in seconds per day from your watch's tick, in about 30 seconds — the same number a timegrapher gives you.
• Every reading carries a confidence score, so you know when to trust it and when to record again.
• Movements from 18,000 to 36,000 bph, detected automatically or set per watch.

ACCURACY OVER TIME — THE PART A TIMEGRAPHER CAN'T DO
A bench reading captures one moment. ChronoLog logs every measurement into timing runs and charts the daily rate as you actually wear the watch: watch it drift, catch magnetization, and see when it needs regulation or a service — before it costs you minutes a week.
• Photo offset: photograph the dial against atomic time for the most precise manual reading.
• Tap timing: tap on the second for a quick log with any watch, quartz included.
• Tag measurements by position, temperature or activity to learn what moves the rate.

ACCURACY REPORT — NEW
A health score for every watch, timekeeping trends per run, and an anonymous comparison against the same models worldwide — find out whether your Submariner or your SKX keeps time better than most. Share a private report link that expires on its own.

ATOMIC TIME
Every measurement is referenced to NTP atomic time, not your phone's clock. Use the live atomic clock, with an optional seconds tick, to set your watches to the second.

YOUR COLLECTION, ORGANISED
• Unlimited watches with photos, brand, model, calibre, serial number, service history and notes.
• Wear log: swipe to mark what you're wearing, then see your rotation as a calendar, timeline and stats.
• Moon phase: last and next full moon with the days between — set a moonphase complication in seconds.
• Full backup and restore. CSV export for your records or your watchmaker.

WHY COLLECTORS CHOOSE CHRONOLOG
A timegrapher is for adjusting a watch. ChronoLog is for knowing it — clean, fast, ad-free, built by a collector in Boulder, Colorado, who reads and answers every review.

Download ChronoLog and find out how your watches really run.

Recent changes:
More coaching in the audio flow. Some deeper telemetry to analyze. New app icon