Watch accuracy, in your pocket
Know exactly how accurate your watch is.
Isochron turns your iPhone into a precision timegrapher. Measure any mechanical watch by ear or by photo, watch its rate build live, and see how yours stacks up against every other owner.
Coming soon to the App Store · iPhone
How it works
Two ways to measure — no extra hardware.
A bench timegrapher costs hundreds and only tells you how the watch behaves resting on a table. Isochron gives you both the bench reading and the number that actually matters: how your watch performs on the wrist.
Listen to the ticks
Rest your phone against the watch and Isochron reads the rate and beat error live, like a professional timegrapher — with a scrolling beat trace you can actually watch converge.
Photograph the dial
Snap the watch face and Isochron timestamps it to the millisecond. Take another a few days later and it calculates your real-world worn accuracy from the drift.
More than a meter
Built for people who love their watches.
See how yours compares
Every reading is placed on the live distribution of other owners running the same model and movement. Find out instantly whether your watch is a star or due for a regulation.
Your digital watch box
Log every watch with photos, specs, and a full accuracy history. Track service intervals and warranties, with reminders so you never miss one.
Trends over time
Watch your watch settle in after a service, spot a magnetized movement early, and keep a regulation log of before-and-after rates.
A community of owners
Share your results, read regulation stories, and talk shop in caliber-specific boards with collectors who care about precision as much as you do.
Be first
Join the waitlist.
Isochron is coming to the App Store for iPhone. Drop your email and we'll tell you the moment it's live.
Thanks — you're on the list.
Questions
Frequently asked
Can an iPhone really measure watch accuracy?
Yes. Isochron listens to the ticks through your microphone and times them like a timegrapher to read the rate and beat error, or measures real-world drift between two timestamped photos of the dial.
What is a good rate for a mechanical watch?
Chronometer-certified watches run within −4 to +6 seconds per day. Most quality mechanical watches sit within about 15 seconds per day. Isochron shows where yours lands and how it compares to other owners of the same movement.
Does it work with any watch?
The acoustic timegrapher works with mechanical (automatic and hand-wound) watches. The photo method works with any analog watch — including quartz — since it measures displayed time against the clock.
Do I need a timegrapher machine or special hardware?
No. Isochron uses only your iPhone's microphone and camera. No bench machine, microphone stand, or accessories required.
Is Isochron free?
Isochron is free to download and measure your watches.