# Big Clock HD vs Atomic Clock PRO

The clearest difference is price: Atomic Clock PRO at Free against Big Clock HD's $0.49. Atomic Clock PRO also leads on rating (4.7 vs 3.0) and update cadence (every 3 months vs every 29 months). Big Clock HD's advantage is in-app purchases (none vs 2) and ads (none vs shown). On iOS requirement there is nothing between them.

Atomic Clock PRO is free to download; Big Clock HD costs $0.49 up front. Atomic Clock PRO sells 2 in-app purchases, starting at $1.99 per month. Big Clock HD asks for nothing beyond the download.

Atomic Clock PRO holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: Atomic Clock PRO has 10K ratings behind it against 23, so its average is the more settled of the two. Written reviews point the same way: 45% of Big Clock HD's written reviews are positive against 73% of Atomic Clock PRO's.

Big Clock HD ships an update every 29 months, Atomic Clock PRO every 3 months. The most recent releases landed on October 9, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Big Clock HD | Atomic Clock PRO |
| --- | --- | --- |
| Price | $0.49 | **Free** |
| Rating | [3.0 (23 ratings)](https://appshunter.io/ios/app/big-clock-hd/id364394834/reviews) | **[4.7 (10K ratings)](https://appshunter.io/ios/app/atomic-clock-pro/id899090224/reviews)** |
| Number of ratings | 23 | **10K** |
| Positive reviews | 45.5% of reviews | **72.9% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 29 months | **Every 3 months** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 1 MB | 6 MB |
| Requires iOS | **14.0** | 15.6 |
| Devices | **iPhone, iPad, iPod, Mac, Apple TV** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [TheCodingMonkeys](https://appshunter.io/developer/284181889) | [Brachmann Online Marketing GmbH & Co. KG](https://appshunter.io/developer/682848918) |

## What reviewers say

### Big Clock HD

[App page](https://appshunter.io/ios/app/big-clock-hd/id364394834)

This app displays a large, easily readable digital clock on your device, perfect for viewing from afar. It supports all iOS locales and can prevent your device from auto-locking while the clock is displayed. Additional features include seconds display and widgets.

**Highlights:** Large, readable date and time display, Supports all iOS locales, Prevents auto-locking, Optional seconds display, Widgets

**Features:** Vision Pro support

**In-app purchases:** none


### Atomic Clock PRO

[App page](https://appshunter.io/ios/app/atomic-clock-pro/id899090224)

Get the most accurate time from an official atomic clock server. This app automatically detects your time zone and allows custom backgrounds. Easily switch between digital and analog clock displays with a swipe.

**Highlights:** Exact time from atomic clock, Automatic time zone recognition, Customizable background images, Digital and analog clock modes, Optional sound alerts, Color customization

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $1.99 | per month |
| Remove Ads | $5.99 | one-time |

**What reviewers like**

- ⭐ Accurate time display
- 📟 Useful for timing events
- 🕰️ Helpful for setting other clocks
- 🔍 Large, easy-to-read clock face

**What reviewers complain about**

- 💸 Subscription model for ad-free version
- 📢 Excessive advertisements
- 🔍 Small font for seconds display
- 🔀 Difficulty in displaying both analog and digital clocks simultaneously

**Reported bugs**

- Second hand occasionally runs in reverse
- Digital clock display cuts off on some devices
- Inconsistent behavior when switching between clock types

**Requested features**

- Customizable clock face options
- Ability to set widget on home screen
- Sync with system clock to automatically update time


## Frequently asked questions

### Is Big Clock HD free?

Big Clock HD costs $0.49, with no in-app purchases.

### Is Atomic Clock PRO free?

Atomic Clock PRO is free to download, with in-app purchases available.

### Which has better reviews, Big Clock HD or Atomic Clock PRO?

Atomic Clock PRO is rated higher. Big Clock HD averages 3.0 out of 5 from 23 ratings, while Atomic Clock PRO averages 4.7 from 10K ratings.

### Do Big Clock HD or Atomic Clock PRO have ads?

Atomic Clock PRO shows ads; Big Clock HD does not.

### Which is updated more often, Big Clock HD or Atomic Clock PRO?

Big Clock HD ships an update every 29 months, and Atomic Clock PRO every 3 months. Most recently, Big Clock HD was updated on October 9, 2026 and Atomic Clock PRO on October 13, 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.*