Comparison

Kello vs Watch Tuner

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Kello

This app analyzes the accuracy of mechanical watches by listening to their ticking sounds through your device's microphone. It compares the watch's rhythm to the precise system clock to reveal timekeeping differences. Supports a wide range of watch frequencies and offers guidance on identifying mechanical timepieces.

Highlights
  • Microphone-based watch sound analysis
  • Comparison to iOS system clock
  • Automatic detection of 8 common watch frequencies
  • Guidance on identifying mechanical watches
  • Displays timekeeping differences
Features
Read full description

Kello analyzes the precision of mechanical watches against the iOS system clock using a microphone. How Kello works: All mechanically regulated watches are designed to start and stop 1000s of times every hour. A portion of the energy used during this starting and stopping motion is released as acoustic energy, resulting in an audible "tick-tock" sound. The regularity of this sound can be measured against the more precise, internal time-signal of iOS devices, such as the iPhone, and the resulting difference in timekeeping is displayed by Kello. Supported Watch Frequencies: Kello can automatically determine the frequency of the watch being measured based on eight of the most common frequencies used in mechanical watches. These frequencies are standard among low-, middle- and high-grade mechanical timepieces and will accommodate the vast majority of mechanical watches produced in the past 100 years. The following frequencies are supported: * 14,400 bph * 16,200 bph * 18,000 bph * 19,800 bph * 21,600 bph * 25,200 bph * 28,800 bph * 36,000 bph Recommended hardware: Kello works best with an external microphone that has an excellent frequency response between 10,000 and 20,000 Hz. How to know if your watch is mechanically regulated: There are four simple ways to determine if your watch is mechanical and can be used with Kello. 1. Look at the text on your timepiece. If the word "quartz" is featured anywhere on the watch, your watch is not mechanical. If the words "automatic" or "shock-proof" are written anywhere on the watch, there is a very high chance that your watch is mechanical and its precision can be measured by Kello. 2. If your watch has a hand that indicates the seconds, observe how frequently it moves. If the hand moves only once every second, it is very likely that your watch is not mechanical. If this hand moves several times per second or appears to sweep along in a smooth, continuous motion, your watch is most likely mechanical and its precision can be measured by Kello. 3. Turn the crown, that is used to set the hands of the watch, while it is pressed fully in. If the crown turns smoothly, your watch is not mechanical. If you can hear a ratcheting sound as you turn the crown, your watch is most likely mechanical and its precision can be measured by Kello. 4. Place the watch close to your ear and listen. If you hear a noise approximately once every second, it is unlikely that your watch is mechanical. If you hear a constant ticking noise, your watch is very likely a mechanical watch and its precision can be measured by Kello.

About

Watch Tuner

This application tests mechanical and automatic watches by measuring rate, beat error, and amplitude using your device's microphone. It provides a history of results for tracking watch quality and stability. For best accuracy, use in a quiet environment.

Highlights
  • Measures rate, beat error, and amplitude
  • Uses device microphone for recording ticks
  • Provides results history
  • Supports iPhone and iPod
  • Quiet environment recommended for accuracy
Features
Read full description

Watch Tuner is a mechanical and automatic watch testing application designed to measure following parameters: - rate - beat error - amplitude - beats per hour The application uses the build-in or headset microphone to record audible ticks of the watch. You can measure now with your iPhone the quality and stability of the rate accuracy, amplitude and beat error of mechanical watch movements. You can also take advantage of results history. Use in a quiet environment. Any ambient noises can affect result accuracy. Complete silence is the best. Recommended way to record the ticks is to touch the crown of the watch with the headset microphone. You will get the best results using original Apple EarPods. If you don't need such advanced tool as Watch Tuner and all you need is to the check rate accuracy, maybe it's worth to try Watch Tuner Lite - a little brother of Watch Tuner application. If you need frequency diagram look at Watch Tuner Timegrapher - the most sophisticated app of Watch Tuner series.

Screenshots

Kello3 screens
Watch Tuner1 screens

Verdict

The call

The clearest difference is rating: Watch Tuner at 3.8 against Kello's 2.8. Watch Tuner also leads on review sentiment (70% vs 37%) and price ($3.99 vs $9.99). Kello's advantage is iOS requirement (13.0 vs 15.6). On ratings volume, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Kello costs $9.99 and Watch Tuner $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Watch Tuner holds the better App Store score, 3.8 against 2.8. Both are backed by a comparable volume of ratings — 5 and 6 respectively. Written reviews point the same way: 37% of Kello's written reviews are positive against 70% of Watch Tuner's.

UpkeepUpdate frequency

Kello ships an update every 3 months, Watch Tuner every 2 months. The most recent releases landed on October 14, 2026 and October 12, 2026 respectively.

Scorecard5 real differences · 5 level
Kello versus Watch Tuner: the parameters behind the verdict, then further details
ParameterKelloWatch Tuner
Price$9.99$3.99 — better
Rating2.8 (5 ratings)3.8 (6 ratings) — better
Positive reviews37.3% of reviews69.6% of reviews — better
Number of ratings56 — better
Update frequencyEvery 3 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPodiPhone, iPod
Requires iOS13.0 — better15.6
Further details — not scored
Size4 MB1 MB
Age rating4+4+
DeveloperColdflower Design Corp.Bartlomiej Swiatek

Customer experience

Kello

All ratings5 ratings
Positive40.0%
Neutral20.0%
Negative40.0%
Written reviews161 reviews
Positive37.3%
Neutral8.1%
Negative54.7%

Watch Tuner

All ratings6 ratings
Positive50.0%
Neutral33.3%
Negative16.7%
Written reviews23 reviews
Positive69.6%
Neutral8.7%
Negative21.7%

Bugs and requests

Kello

Reported bugs

10 issues
  • App crashes on iPhone 5 and iOS 6
  • Signal detection fails inconsistently
  • Frequency auto-detection varies wildly on same watch
  • Unstable signal readings despite strong initial signal
  • App hangs on 'determine frequency' step
Show 5 more
  • Poor microphone compatibility with external mics
  • Results vary significantly between consecutive measurements
  • Crashes frequently during measurement process
  • Incompatibility with newer iOS versions
  • Microphone not detected on some devices

Requested features

10 requests
  • History log and data storage for watches
  • Graphical representation of timing data over time
  • Average readings over longer time periods
  • Watch profile saving functionality
  • Beat error measurement capability
Show 5 more
  • Export feature for timing results
  • Fine-tuning control for amplification slider
  • Improved signal detection algorithm
  • Better microphone sensitivity recommendations
  • Compatibility with more iOS versions

Watch Tuner

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Kello

No in-app purchases

None

Watch Tuner

No in-app purchases

Questions

Is Kello free?
Kello costs $9.99, with no in-app purchases.
Is Watch Tuner free?
Watch Tuner costs $3.99, with no in-app purchases.
Which has better reviews, Kello or Watch Tuner?
Watch Tuner is rated higher. Kello averages 2.8 out of 5 from 5 ratings, while Watch Tuner averages 3.8 from 6 ratings.
Do Kello or Watch Tuner have ads?
Neither Kello nor Watch Tuner shows ads.
Which is updated more often, Kello or Watch Tuner?
Kello ships an update every 3 months, and Watch Tuner every 2 months. Most recently, Kello was updated on October 14, 2026 and Watch Tuner on October 12, 2026.

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