# Big Time Clock vs Atomic Exact Time

The clearest difference is price: Atomic Exact Time at Free against Big Time Clock's $3.49. Atomic Exact Time also leads on iOS requirement (16.4 vs 18.6). Big Time Clock's advantage is rating (5.0 vs 4.0) and in-app purchases (none vs 1). On ratings volume, update cadence, ads and device support there is nothing between them.

Atomic Exact Time is free to download; Big Time Clock costs $3.49 up front. Atomic Exact Time sells 1 in-app purchase, starting at $2.99 per month. Big Time Clock asks for nothing beyond the download.

Big Time Clock holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Big Time Clock ships an update every 3 weeks, Atomic Exact Time every 6 weeks. The most recent releases landed on October 12, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Big Time Clock | Atomic Exact Time |
| --- | --- | --- |
| Price | $3.49 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/big-time-clock-full-screen/id6763140176/reviews)** | [4.0 (1 ratings)](https://appshunter.io/ios/app/atomic-exact-time-clock/id6797418012/reviews) |
| Number of ratings | 1 | 1 |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 6 weeks |
| Monetization | Paid | **Free with in-app purchases** |
| Best chart rank | **#150** | — |
| Size | 1 MB | 46 MB |
| Requires iOS | 18.6 | **16.4** |
| Devices | iPhone, iPad | **iPhone, iPad, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Matthew Avery](https://appshunter.io/developer/1893424317) | [SUPER KIM KIMYA VE TEKSTIL SANAYI TICARET LIMITED SIRKETI](https://appshunter.io/developer/1896542696) |

## What reviewers say

### Big Time Clock

[App page](https://appshunter.io/ios/app/big-time-clock-full-screen/id6763140176)

**Currently charting:** #150 Top Paid · Utilities (US App Store)

Transform your device into a large, easy-to-read full-screen clock for any room. Enjoy a clear display with customizable typography and orientation, perfect for a nightstand or desk. This app offers a one-time purchase with all features unlocked, no ads or subscriptions.

**Highlights:** Full-screen digital clock, Elegant analog face, Always-on display, Portrait and landscape modes, Customizable typography, Day and date display

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Atomic Exact Time

[App page](https://appshunter.io/ios/app/atomic-exact-time-clock/id6797418012)

This app precisely calibrates your device's clock against internet time sources, accounting for network delays. It offers a full-screen display with millisecond accuracy, detailed reports on clock deviation, and a precision alarm. Ideal for professionals and enthusiasts requiring exact timing.

**Highlights:** Millisecond accurate clock display, Device offset status, Network latency and drift reports, Precision alarm, Timecode and markers, Widgets, Multiple clock themes

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Atomic Exact Time Pro | $2.99 | per month |


## Frequently asked questions

### Is Big Time Clock free?

Big Time Clock costs $3.49, with no in-app purchases.

### Is Atomic Exact Time free?

Atomic Exact Time is free to download, with in-app purchases available.

### Which has better reviews, Big Time Clock or Atomic Exact Time?

Big Time Clock is rated higher. Big Time Clock averages 5.0 out of 5 from 1 ratings, while Atomic Exact Time averages 4.0 from 1 ratings.

### Do Big Time Clock or Atomic Exact Time have ads?

Neither Big Time Clock nor Atomic Exact Time shows ads.

### Which is updated more often, Big Time Clock or Atomic Exact Time?

Big Time Clock ships an update every 3 weeks, and Atomic Exact Time every 6 weeks. Most recently, Big Time Clock was updated on October 12, 2026 and Atomic Exact Time on October 14, 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.*