# ClockMaster vs AtomicClock

The clearest difference is price: AtomicClock at Free against ClockMaster's $49.99. AtomicClock also leads on rating (4.8 vs 3.8) and update cadence (every 3 weeks vs every 5 months). ClockMaster's advantage is ads (none vs shown). On in-app purchases and monetization model there is nothing between them.

AtomicClock is free to download; ClockMaster costs $49.99 up front. ClockMaster sells 1 one-off in-app purchase and AtomicClock sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

AtomicClock holds the better App Store score, 4.8 against 3.8. That said, the two scores are not equally well evidenced: AtomicClock has 5.5K ratings behind it against 52, so its average is the more settled of the two. Written reviews point the same way: 59% of ClockMaster's written reviews are positive against 85% of AtomicClock's.

ClockMaster ships an update every 5 months, AtomicClock every 3 weeks. The most recent releases landed on September 23, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | ClockMaster | AtomicClock |
| --- | --- | --- |
| Price | $49.99 | **Free** |
| Rating | [3.8 (52 ratings)](https://appshunter.io/ios/app/clockmaster-time-regulator/id413901882/reviews) | **[4.8 (5.5K ratings)](https://appshunter.io/ios/app/atomicclock-ntp-time/id1402993049/reviews)** |
| Number of ratings | 52 | **5.5K** |
| Positive reviews | 58.6% of reviews | **84.5% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 5 months | **Every 3 weeks** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 5 MB | 17 MB |
| Requires iOS | 18.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [ONYX Apps](https://appshunter.io/developer/356553882) | [Timo Partl](https://appshunter.io/developer/1387413672) |

## What reviewers say

### ClockMaster

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

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


### AtomicClock

[App page](https://appshunter.io/ios/app/atomicclock-ntp-time/id1402993049)

This app displays the exact current time synchronized with NTP servers, offering a customizable clock view for precise time checks. It's ideal for setting watches, verifying timestamps, or comparing local and network time.

**Highlights:** Precise time from NTP servers, Customizable clock faces, Select or add time servers, Local and UTC views, 12/24 hour modes, Customizable time format, Acoustic ticking

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Pro Version | $6.99 | one-time |

**What reviewers like**

- 🚀 Accurate time
- 👍 Highly customizable
- 🚀 Precise to the second
- 👍 Easy to use
- 👍 Helpful for setting watches

**What reviewers complain about**

- 🐛 Server connection issues
- 🔍 Limited time zone options
- 💰 Ads diminish clock view
- 🔍 Lacks some advanced features
- 🔍 Redundant for some users

**Reported bugs**

- Crashes on certain iOS versions
- Occasional freezing of hands
- Countdown timer sound not working

**Requested features**

- Add GMT/dual time display
- Implement widget support
- Add different second hand sounds
- Allow setting background color to match watch
- Include alarm/timer functionality


## Frequently asked questions

### Is ClockMaster free?

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

### Is AtomicClock free?

AtomicClock is free to download, with in-app purchases available.

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

AtomicClock is rated higher. ClockMaster averages 3.8 out of 5 from 52 ratings, while AtomicClock averages 4.8 from 5.5K ratings.

### Do ClockMaster or AtomicClock have ads?

AtomicClock shows ads; ClockMaster does not.

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

ClockMaster ships an update every 5 months, and AtomicClock every 3 weeks. Most recently, ClockMaster was updated on September 23, 2026 and AtomicClock on September 24, 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.*