ChronoLog • Watch Accuracy

ChronoLog — Watch Accuracy Tracker & Audio Timegrapher for Mechanical Watches

Track the accuracy of your mechanical watches with professional-grade tools. ChronoLog combines an audio timegrapher, offset measurement logging, and atomic time synchronization into one app — purpose-built for watch collectors and horology enthusiasts who care about precision.

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

MEASURE WATCH ACCURACY — THREE WAYS

• Audio Timegrapher: Use your device's microphone to listen to your watch's tick and measure rate (seconds per day), beat error, and amplitude — the same metrics a professional timegrapher provides.

• Photo Offset: Photograph your watch dial against atomic time, enter the displayed time, and ChronoLog calculates the exact offset. The most precise manual method for measuring watch accuracy.

• Tap Timing: Tap when your watch hits a specific second to quickly log an offset. Fast, simple, and works with any watch.

TRACK ACCURACY OVER TIME

Each measurement is logged to a timing run — a series of readings that ChronoLog analyzes together. Monitor your watch's daily rate, see how accuracy changes day to day, and spot regulation issues before they become problems. Tag measurements with conditions like position, temperature, or wear pattern to understand what affects your watch's performance.

ATOMIC TIME SYNCHRONIZATION

ChronoLog syncs with NTP atomic time servers so every measurement is referenced against true time — not your phone's clock. View the live atomic time, compare it to your device, and use it as a precision reference when setting your watches.

DETAILED ANALYTICS & VISUALIZATIONS

Dive into performance graphs that show rate trends, offset history, and accuracy patterns across your entire collection. See at a glance which watches in your collection are your most accurate daily wearers and which need regulation or service.

BUILT FOR WATCH COLLECTORS

• Add unlimited watches with photos, brand, model, serial number, caliber, and notes
• Organize your collection with archive support
• Export all measurement data to CSV for your records or your watchmaker
• Back up and restore your full database across devices

WHY CHRONOLOG?

Whether you're a seasoned collector checking COSC-grade accuracy, a hobbyist curious about your Seiko's daily rate, or a watchmaker tracking regulation results — ChronoLog gives you the tools to measure, log, and understand your watch's timekeeping performance.

Built by a watch enthusiast in Boulder, Colorado.

Download ChronoLog and start measuring your watch accuracy today.