# 504 vs Atom School

The clearest difference is in-app purchases: Atom School at none against 504's 7. Atom School also leads on ads (none vs shown) and iOS requirement (13.0 vs 18.0). 504's advantage is update cadence (fortnightly vs every 20 months). On price and device support there is nothing between them.

Both are free to download. 504 sells 6 in-app purchases, starting at $4.99 per 7 days. Atom School asks for nothing beyond the download.

504 ships an update fortnightly, Atom School every 20 months. The most recent releases landed on November 2, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | 504 | Atom School |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (4.6K ratings)](https://appshunter.io/ios/app/504-vocabulary-builder/id1452101398/reviews)** | — |
| Number of ratings | **4.6K** | — |
| Positive reviews | 73.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Fortnightly** | Every 20 months |
| Monetization | Free with in-app purchases | — |
| Size | 66 MB | 27 MB |
| Requires iOS | 18.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Nefarius Apps](https://appshunter.io/developer/1792473508) | [meisam mirahsan](https://appshunter.io/developer/1466980802) |

## What reviewers say

### 504

[App page](https://appshunter.io/ios/app/504-vocabulary-builder/id1452101398)

Master essential vocabulary with this language learning app. It offers clear definitions, example sentences, and native pronunciation for high-utility words. Engage with interactive games like flashcards and quizzes to reinforce learning and track your progress effectively.

**Highlights:** Essential vocabulary selection, Clear definitions and example sentences, Native pronunciation audio, Interactive learning games (flashcards, quizzes), Progress tracking tools, Multi-language support

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

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $4.99 | per 7 days |
| Premium | $9.99 | per month |
| Premium | $9.99 | per month |
| Premium | $9.99 | per 7 days |
| Premium | $34.99 | per year |
| Yearly Pro Membership | $59.99 | per year |

**What reviewers like**

- 🚀 Easy to learn
- 👍 Useful vocabulary practice
- 🚀 Convenient for learning on the go

**What reviewers complain about**

- 🐛 Bugs and glitches in latest version
- 🔒 Concerns about data tracking
- 🔊 Issues with pronunciation and audio

**Reported bugs**

- Pronunciation not working in latest version
- Lessons for second half of book blocked behind paywall
- Compatibility issues with older devices

**Requested features**

- Add part of speech for each word
- Include a note box for personal examples
- Add dark mode option


### Atom School

[App page](https://appshunter.io/ios/app/atom-school/id6450889080)

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

**In-app purchases:** none


## Frequently asked questions

### Is 504 free?

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

### Is Atom School free?

Atom School is free to download, with no in-app purchases.

### Do 504 or Atom School have ads?

504 shows ads; Atom School does not.

### Which is updated more often, 504 or Atom School?

504 ships an update fortnightly, and Atom School every 20 months. Most recently, 504 was updated on November 2, 2026 and Atom School on October 25, 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.*