# Radioactivity Conversion vs Twilight Time

The clearest difference is price: Twilight Time at Free against Radioactivity Conversion's $2.99. Twilight Time also leads on update cadence (every 2 weeks vs every 28 months). Radioactivity Conversion's advantage is ads (none vs shown) and iOS requirement (13 vs 16.7.10). On in-app purchases and device support there is nothing between them.

Twilight Time is free to download; Radioactivity Conversion costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Radioactivity Conversion ships an update every 28 months, Twilight Time every 2 weeks. The most recent releases landed on September 30, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | Radioactivity Conversion | Twilight Time |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/radioactivity-conversion/id561349846/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 28 months | **Every 2 weeks** |
| Monetization | Paid | — |
| Size | 1 MB | 36 MB |
| Requires iOS | **13** | 16.7.10 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) |

## What reviewers say

### Radioactivity Conversion

[App page](https://appshunter.io/ios/app/radioactivity-conversion/id561349846)

Easily convert between various units related to radioactive decay. Understand the process of emitting radioactive particles and the properties of elements exhibiting radioactivity.

**Highlights:** Radioactive decay unit conversion, Information on radioactive decay process, Details on radioactive particles, Explanation of half-life, Properties of radioactive elements

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

**In-app purchases:** none


### Twilight Time

[App page](https://appshunter.io/ios/app/twilight-time/id6503278537)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Radioactivity Conversion free?

Radioactivity Conversion costs $2.99, with no in-app purchases.

### Is Twilight Time free?

Twilight Time is free to download, with no in-app purchases.

### Do Radioactivity Conversion or Twilight Time have ads?

Twilight Time shows ads; Radioactivity Conversion does not.

### Which is updated more often, Radioactivity Conversion or Twilight Time?

Radioactivity Conversion ships an update every 28 months, and Twilight Time every 2 weeks. Most recently, Radioactivity Conversion was updated on September 30, 2026 and Twilight Time on October 9, 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.*