Turn your iPhone into a timegrapher: rate in seconds per day from the mic, each reading confidence-scored. Track accuracy over time. One-time purchase.
ChronoLog — Timegrapher, Watch Accuracy Tracker & Collection Log
Turn your iPhone 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.
I just recently got into automatic/mechanical watches, and was looking for a way to measure the accuracy of my timepieces. ChronoLog is straightforward, very easy to use and intuitive. I love that the offset, change and rate are all displayed for you, as well as the graphs that help you visualize the changes. Adding a measurement and/or point is also very straightforward.The ability to personalize each watch with a picture and details of the brand, model, purchase date and purchase price are also nice. When you’ve got multiple watches entered into the app, it really gives you a sense of collection whenever you open ChronoLog.Overall, I think ChronoLog is a solid app for watch enthusiasts.
Developer Response
Can't thank you enough for using my app and for taking the time to share this review. If you ever have any feedback or ideas that would make this app more useful, I'm all ears!
an absolute steal for the functionality
Damon-L
this is my first review on the app store in YEARS. i really can’t remember the last one i did. for the price of entry for this app you get full forever access to catalog your watches with their pertinent data, purchase date, price paid, etc. and with very easily tracking of how slow or fast your watches are running with historical data to see trends over time, as well as the perfect analog clock WITH haptic feedback per second to set your watch right on time very easily. app is attractive and minimalistic to a degree with only the important info displayed. this is the perfect app for someone wanting to casually keep up with watch accuracy.
Developer Response
Thanks for the review! It's a labor of love to build and maintain this side project. Hearing from people who enjoy it is a great reward.
Best app I’ve tried yet to track my watches
snakej200
This app pretty much does all you could ask: logs your wear time, tracks your watches accuracy by both manual input and the ability to take a picture, as well as work as a Timegrapher which admittedly I haven’t tried that feature since I have an actual Timegrapher. The other feature are pretty much flawless and the app is laid out extremely user friendly. I really like the fact that it gives you stats on what watch you wear the most/least, most recent, and what hasn’t been on your wrist in a long time. Just buy this app you won’t be disappointed
Developer Response
I appreciate you taking the time to leave a kind review! If you have any feedback in the future, please feel free to reach out!
Great App. Great Price.
This app is so worth it!!
Amazing app. Does what all the other apps do but more for so much less money. This app/tool is worth so much more than the $4 one time payment. Other apps charge a monthly fee of like $6 but do less than this and that just crazy. My favorite features are the ability to see the movement of the watch in 3D and the vibration clicks per seconds help me set the accuracy so well. 10/10 app. If you’re a watch enthusiast or even just starting the hobby I couldn’t recommend this app more.
Developer Response
Thanks for taking the time to leave a review! I'm glad you feel that it is a good value for the price. I'm very proud to deliver a premium product and experience for watch collectors without exploitative subscription pricing. It makes it harder for me because I don't have money for marketing like my competitors, but I hope word of mouth can do the job :)
Accuracy Report
• A health score for every watch, timekeeping trends by timing run, and an anonymous comparison against the same models worldwide.
• Open it from the Info tab or from any watch. Share a private link that expires on its own.
• Your watch photos now appear in the report.
Timegrapher
• Every audio reading now shows a confidence score, so you know when to trust it.
• Clearer per-run detail in audio results.
Moon phase
• Last and next full moon with days since and until — the numbers you set a moonphase complication from.
• The moon is now drawn correctly in light mode and for your hemisphere.
Fixes
• Clear error messages when the camera or cropper fails.
• Photo measurements now apply the atomic-time correction.
• The audio screen no longer crowds the Listen button.
• The listing now shows the app's German and Spanish localizations.
Version 2.6.0
The developer, tyler wood, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
Purchases
User Content
Identifiers
Usage Data
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
