Turn your iPhone or iPad into a timegrapher and track your watch's accuracy against atomic time. Version 1.7.1 20 languages
Chronograde measures how a mechanical watch is running — live rate and beat error read acoustically through your device's microphone — and tracks each watch's daily drift against true atomic time over days and weeks. It runs on both iPhone and iPad. Add as many watches as you like, see how each grades against COSC and METAS chronometer standards, compare accuracy by position across sessions, log wear and service history, set your watch against an NTP-corrected clock, and export everything to CSV or Excel. Chronograde is free to use, supported by ads on the free tier; an optional Chronograde Pro upgrade (subscription or a one-time Lifetime unlock) removes every ad and adds unlimited measurements, Regulation Coach, Accuracy by Position, your Chronometer Score, the Atomic Clock, wear & service logs and export. Your watch data stays on your device and, if you choose, your own iCloud.
14:30:20) — and press RECORD the instant the second hand touches it. After your second reading the drift chart and average rate per day fill in automatically.On the free tier, yes — and Chronograde Pro removes them entirely. The free tier carries a banner at the bottom of the screen and an occasional full-screen ad when you return to the Watches list. Ads never cover the controls, and never appear during a measurement or a Timegrapher session. Advertising is supplied by Unity Ads; see the privacy policy for what it collects and how to opt out of personalised ads.
The Timegrapher is free for everyone — measure any watch's rate and beat error at no cost, with no account. You can also add your whole collection and record up to 10 accuracy measurements free. Chronograde Pro adds unlimited measurements and sessions, Regulation Coach, Accuracy by Position, your Chronometer Score, the Atomic Clock, wear & service logs, and export to CSV & Excel.
You can record up to 10 measurements across all watches for free. Chronograde Pro unlocks unlimited measurements and the full Pro feature set. It's available as a monthly or annual auto-renewable subscription (each with a 14-day free trial for new subscribers), or as a one-time Lifetime unlock — pay once and own Pro forever, with no subscription. Subscriptions renew automatically until cancelled; manage or cancel anytime from iOS Settings → [your name] → Subscriptions. Tap Restore Purchases on the membership screen if you've bought Pro before on the same Apple ID.
For drift tracking, Chronograde uses SNTP (RFC 4330) to query a public time service and applies the offset to your device's clock — accurate to well under a tenth of a second. The bottleneck is your reaction time pressing RECORD as the second hand touches the target; press it consistently and the math averages out over multiple readings. For the acoustic Timegrapher, rest the phone firmly on the caseback in a quiet room and let the reading stabilize for a few seconds.
It depends on the watch. COSC chronometer-certified mechanical watches must run within −4/+6 seconds per day. ETA standard movements typically run ±10–30 s/day. Quartz watches usually run ±0.5 s/day or better. Chronograde colors the rate green up to ±10 s/day, orange up to ±30, and red beyond that.
Chronograde uses UDP on port 123 for SNTP queries. Some corporate, hotel, or captive Wi-Fi networks block outbound UDP. Try a different network or use cellular, then tap the sync icon in the top-right of the Watches tab. Without a successful sync, measurements fall back to the device clock and are marked accordingly.
If iCloud (CloudKit) is enabled for Chronograde and you're signed in with the same Apple ID on both devices, your watches, measurements, wear log, and service history sync automatically. Settings → iCloud shows the current status.
Yes. From the Watches tab menu, choose Export to Excel (a workbook with Watches, Measurements, Wear, and Service sheets) or Export to CSV. You can also import a watches CSV the same way; Chronograde detects duplicates by serial number or brand + model + nickname.
Please email mwsupplylimited@gmail.com with your iOS version, device, and steps to reproduce. We read every message.
For support: mwsupplylimited@gmail.com
See the Chronograde Privacy Policy.