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Ratewell
Watch Timegrapher
Turn your iPhone into a precision timegrapher for your watches
Ratewell is an iPhone app by Develak that turns your iPhone into a timegrapher for mechanical watches, letting collectors measure rate, amplitude, and beat error, then track each watch’s accuracy over time.
- Age
- 4+ years old
- Category
- Utilities
- Price
- Free In-app purchases
- Languages
- 44 EN · FR +42
- Requires
- iOS 17+ iPhone · iPad
- Size
- 4.9 MB
- Version
- 1.0
Screenshots
See Ratewell in action
iPhone
iPad
Overview
What is Ratewell?
Ratewell measures mechanical watches the way a watchmaker’s machine does, but using nothing more than your iPhone’s microphone. Hold your watch close, and within seconds you get a live reading of rate, amplitude, and beat error, calibrated to stay accurate even in a noisy room.
Beyond a single reading, Ratewell keeps every measurement, building a long-term accuracy history for each watch. Add your watches to a collection with details like brand, caliber, and service dates, then track drift, compare positions, and export a report when it’s time to see your watchmaker.
Read the full App Store description
Ratewell turns your iPhone into a precision timegrapher for mechanical watches. Hold your watch to the microphone and read rate, amplitude and beat error in seconds — the same measurements a watchmaker’s machine gives you, without the costly hardware.
But a single reading is only the start. Ratewell logs every measurement to build the one thing other apps don’t: a long-term accuracy history for each watch in your collection.
Measure like a watchmaker
- Live timegrapher: rate (seconds/day), amplitude and beat error from your microphone
- Calibrated signal detection that stays steady through ambient noise
- Six-position analysis: dial up/down, crown left/right and more — see positional variance and isochronism
- Chronometer (COSC) tolerance reference so you instantly know if a reading is in spec
Track accuracy over time
- Automatic rate-history chart per watch — every measurement, plotted
- Spot drift and regulation issues before they cost you a service
- Compare positions, sessions and trends across your whole collection
A real collection & service book
- Unlimited watches: brand, model, caliber, reference, purchase date, photos
- Service log and reminders: last service, interval, warranty, power reserve
- Wear tracking and rotation — know what you wear and what sits idle
- Export a clean PDF accuracy certificate or CSV for your watchmaker
Yours, everywhere
- iCloud sync and backup across iPhone and iPad
- Home-screen widgets for today’s rate and the next service due
- Designed dark-first, like a real timing machine, with tabular figures throughout
Free to measure — always
The timegrapher and the data you save are never locked behind a paywall. Measure, log and read your full history for free, forever.
Ratewell Pro
Unlock the complete instrument: unlimited watches, six-position analysis, isochronism and long-term trends, service reminders, wear tracking, iCloud sync, widgets and export.
- Monthly or Annual subscription — the Annual plan includes a 7-day free trial
- Or pay once with Lifetime — no subscription, ever
Built for collectors who care about precision, from a vintage automatic to a modern chronometer.
—
Ratewell Pro is an auto-renewable subscription. Payment is charged to your Apple ID at confirmation of purchase. The subscription renews automatically unless it is cancelled at least 24 hours before the end of the current period; your account is charged for renewal within 24 hours before the period ends. Manage or cancel your subscription anytime in your App Store account settings. A Lifetime one-time purchase is also available. Any unused portion of a free trial is forfeited when you buy a subscription.
Privacy Policy: https://develak.com/privacy-policy/
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Highlights
What can you do with Ratewell?
Ratewell turns your iPhone into a precision timegrapher, measuring rate, amplitude, and beat error to track your mechanical watches’ accuracy over time.
Live timegrapher readings
Hold your watch to the microphone to get an instant rate, amplitude, and beat error reading.
Six-position analysis
Measure your watch across six positions to see positional variance and isochronism.
Chronometer tolerance reference
Compare your readings against COSC tolerance to see instantly if a watch is in spec.
Automatic rate-history charts
Every measurement is plotted on a chart so you can spot drift before it becomes a problem.
Service log and reminders
Record last service, interval, warranty, and power reserve for each watch you own.
PDF and CSV export
Generate a clean accuracy certificate or CSV file to share with your watchmaker.
Who it’s for
Who is Ratewell for?
-
Watch collectors
For anyone tracking the accuracy of more than one mechanical watch over time.
-
Vintage watch owners
For checking how an older automatic movement is running before deciding on a service.
-
Watchmaking enthusiasts
For anyone curious about reading rate, amplitude, and beat error like a professional.
-
Collectors preparing for a service visit
For building a clear accuracy record to bring to a watchmaker.
How it works
How does Ratewell work?
From “Hold your watch to the microphone” to “Export when you need a record”, in 5 steps.
Hold your watch to the microphone
Place the watch close to your iPhone’s microphone and let Ratewell listen to its ticking.
Read the live measurement
See rate, amplitude, and beat error appear within seconds.
Add the watch to your collection
Record its brand, model, caliber, reference, and photos.
Repeat across positions and over time
Measure dial up, dial down, crown left, crown right, and more, then watch the rate-history chart build.
Export when you need a record
Generate a PDF or CSV to share with your watchmaker.
In depth
Ratewell, in detail
How does Ratewell measure a watch’s accuracy?
Ratewell listens to your watch’s ticking through your iPhone’s microphone and turns the sound into a rate reading in seconds per day, an amplitude reading, and a beat error reading, the same three measurements a watchmaker’s timing machine produces.
The app’s signal detection is calibrated to stay steady even with some ambient noise in the room, so you don’t need a silent space to get a usable reading.
What is six-position analysis in Ratewell?
A mechanical watch can run at a different rate depending on how it’s oriented, for example dial up, dial down, or crown left. Ratewell’s six-position analysis has you measure the watch in each orientation so you can see the positional variance and isochronism side by side.
This is part of "Ratewell Pro", which also unlocks the long-term trend view across positions and sessions.
How does Ratewell track a watch’s service history?
Each watch in your collection has its own service log, where you can record the last service date, the service interval, warranty information, and power reserve. Ratewell can also remind you when the next service is due.
Alongside the service log, the app keeps wear tracking so you can see what you actually wear and what has been sitting idle, and it generates a PDF accuracy certificate or CSV export to bring to your watchmaker. Service reminders, wear tracking, and export are part of "Ratewell Pro".
Release notes
What’s new in Ratewell
Version
1.0
This is the first version of Ratewell, released on June 26, 2026.
FAQ
Ratewell: your questions, answered
Something else? The Ratewell support page covers purchases, sync and settings, and lets you write to us directly.
Is Ratewell free?
Yes. Ratewell is free to download from the App Store. Optional in-app purchases unlock extra features; they are billed by Apple to your Apple Account, and you can manage them at any time in your account settings.
Which devices does Ratewell work on?
Ratewell works on iPhone and iPad with iOS 17.0 or later.
What can I do with Ratewell for free?
You can use the live timegrapher to measure rate, amplitude, and beat error, log every reading, and read your full measurement history at no cost.
What does "Ratewell Pro" unlock?
"Ratewell Pro" unlocks unlimited watches, six-position analysis with isochronism, long-term trend views, service log reminders, wear tracking, iCloud sync, home-screen widgets, and PDF or CSV export.
How do I take a measurement with Ratewell?
Hold your watch close to your iPhone’s microphone and Ratewell reads rate, amplitude, and beat error within seconds.
What do rate, amplitude, and beat error tell me about a watch?
Rate is how many seconds a day the watch gains or loses, amplitude reflects the swing of the balance wheel, and beat error measures the timing difference between the two halves of that swing; Ratewell reports all three from a single reading.
How does Ratewell check if a watch is within chronometer tolerance?
Ratewell compares your live rate reading against the COSC chronometer tolerance reference so you can see immediately whether it falls in spec.
Can I track more than one watch in Ratewell?
Yes, you can add each watch to your collection with details like brand, model, caliber, reference, purchase date, and photos; tracking an unlimited number of watches is part of "Ratewell Pro".
What languages is Ratewell available in?
Ratewell is available in 44 languages: Arabic, Bangla, Catalan, Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish, Dutch, English, Finnish, French, German, Greek, Gujarati, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Kannada, Korean, Malay, Malayalam, Marathi, Norwegian Bokmål, Odia, Polish, Portuguese, Punjabi, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Tamil, Telugu, Thai, Turkish, Ukrainian, Urdu and Vietnamese.
How do I get help with Ratewell?
Visit the Ratewell support page: it answers common questions about purchases, sync and settings, and has a contact form. You can also write to contact@develak.com. We read every message and reply personally.
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