# Kello vs ClockMaster

The clearest difference is price: Kello at $9.99 against ClockMaster's $49.99. Kello also leads on in-app purchases (none vs 1) and iOS requirement (13.0 vs 18.0). ClockMaster's advantage is rating (3.8 vs 2.8) and review sentiment (59% vs 37%). On update cadence, ads and device support there is nothing between them.

Kello costs $9.99 and ClockMaster $49.99 up front. ClockMaster sells 1 one-off in-app purchase. Kello asks for nothing beyond the download.

ClockMaster holds the better App Store score, 3.8 against 2.8. That said, the two scores are not equally well evidenced: ClockMaster has 52 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 37% of Kello's written reviews are positive against 59% of ClockMaster's.

Kello ships an update every 3 months, ClockMaster every 5 months. The most recent releases landed on October 10, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Kello | ClockMaster |
| --- | --- | --- |
| Price | **$9.99** | $49.99 |
| Rating | [2.8 (5 ratings)](https://appshunter.io/ios/app/kello/id380539253/reviews) | **[3.8 (52 ratings)](https://appshunter.io/ios/app/clockmaster-time-regulator/id413901882/reviews)** |
| Number of ratings | 5 | **52** |
| Positive reviews | 37.3% of reviews | **58.6% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 5 months |
| Monetization | **Free** | Free with in-app purchases |
| Best chart rank | — | **#182** |
| Size | 4 MB | 5 MB |
| Requires iOS | **13.0** | 18.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Coldflower Design Corp.](https://appshunter.io/developer/380539256) | [ONYX Apps](https://appshunter.io/developer/356553882) |

## What reviewers say

### Kello

[App page](https://appshunter.io/ios/app/kello/id380539253)

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:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- 💡 Innovative watch timing solution at affordable price
- ✅ Accurate readings when properly configured
- 🎯 Correctly identifies beat frequency (BPH)
- ⚙️ Useful for watch regulation and adjustment
- 📱 Portable alternative to expensive timing machines

**What reviewers complain about**

- 🎙️ Highly sensitive to microphone quality and placement
- 🔇 Requires extremely quiet environment to function
- 📊 Inconsistent readings even in same position
- ⚠️ Frequent signal detection failures
- 🔄 High variability in results between measurements

**Reported bugs**

- 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

**Requested features**

- 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


### ClockMaster

[App page](https://appshunter.io/ios/app/clockmaster-time-regulator/id413901882)

**Currently charting:** #182 Top Paid · Utilities (US App Store)

This app analyzes the ticking sound of mechanical pendulum clocks to determine their running rate and error. It's designed for accurate long-term measurements, allowing users to regulate clocks efficiently. Advanced features include printable reports and data export for in-depth analysis.

**Highlights:** Analyzes escapement ticking sound, Measures running rate in Beats Per Hour (B/H), Reports error in Seconds Per Day (±S/D), Supports long-term measurements, Generates printable PDF reports (Pro), Exports raw data as .csv file (Pro)

**Features:** Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| ClockMaster Pro | $29.99 | one-time |

**What reviewers like**

- 👍 Works very well
- 👍 Accurately sets beat and calibrates time
- 👍 Good alternative to expensive dedicated instruments
- 👍 Elegant display for setting beat and symmetry
- 👍 Works well for professional clock repairers

**What reviewers complain about**

- 😞 Frustrating data handling
- 😞 Spreadsheet export issues
- 😞 iPhone notifications stop measurements
- 😞 Does not work for 400-day clocks
- 😞 External mic option missing

**Reported bugs**

- Data lost if app stops unexpectedly
- iPhone notifications interrupt measurements
- External mic option not available
- App freezes after iOS upgrade
- Screen touch points unresponsive

**Requested features**

- Printable protocol like a timegrapher
- Beat delta info on regulation screen
- Option to manually restart measurement and append
- Undocumented units in spreadsheet export
- Include actual time in spreadsheet export


## Frequently asked questions

### Is Kello free?

Kello costs $9.99, with no in-app purchases.

### Is ClockMaster free?

ClockMaster costs $49.99, and also offers in-app purchases.

### Which has better reviews, Kello or ClockMaster?

ClockMaster is rated higher. Kello averages 2.8 out of 5 from 5 ratings, while ClockMaster averages 3.8 from 52 ratings.

### Do Kello or ClockMaster have ads?

Neither Kello nor ClockMaster shows ads.

### Which is updated more often, Kello or ClockMaster?

Kello ships an update every 3 months, and ClockMaster every 5 months. Most recently, Kello was updated on October 10, 2026 and ClockMaster on October 8, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*