# Decay calc vs RadexM

The clearest difference is review sentiment: RadexM at 100% against Decay calc's 50%. RadexM also leads on rating (4.8 vs 1.0) and in-app purchases (none vs 1). Decay calc's advantage is device support (3 vs 1). On price, ads and iOS requirement there is nothing between them.

Both are free to download. Decay calc sells 1 one-off in-app purchase. RadexM asks for nothing beyond the download.

RadexM holds the better App Store score, 4.8 against 1.0. That said, the two scores are not equally well evidenced: RadexM has 19 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 50% of Decay calc's written reviews are positive against 100% of RadexM's.

Decay calc ships an update every 3 months, RadexM every 3 weeks. The most recent releases landed on October 8, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | Decay calc | RadexM |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/decay-calc/id1479526735/reviews) | **[4.8 (19 ratings)](https://appshunter.io/ios/app/radexm/id1524841479/reviews)** |
| Number of ratings | 1 | **19** |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 27 MB | 113 MB |
| Requires iOS | **15.2** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [Alexey Baranov](https://appshunter.io/developer/1479526734) | [KVARTA-RAD, OOO](https://appshunter.io/developer/1524841481) |

## What reviewers say

### Decay calc

[App page](https://appshunter.io/ios/app/decay-calc/id1479526735)

This tool calculates the decay of radioactive isotopes over time, considering half-life for accurate activity predictions. It's useful in nuclear medicine, environmental monitoring, and radiation safety for handling and disposal of materials.

**Highlights:** Radioactive isotope decay calculation, Half-life integration, Activity prediction, Decay constant determination, Radiation dose calculation

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Radio calc | $0.99 | one-time |


### RadexM

[App page](https://appshunter.io/ios/app/radexm/id1524841479)

This utility app enhances the functionality of RADEX devices by allowing easy settings adjustments and providing a history of measurements. View your data in graphical or tabular formats after connecting via Bluetooth.

**Highlights:** Bluetooth device connection, Quick settings changes, Measurement history tracking, Graphical data display, Tabular data display

**In-app purchases:** none


## Frequently asked questions

### Is Decay calc free?

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

### Is RadexM free?

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

### Which has better reviews, Decay calc or RadexM?

RadexM is rated higher. Decay calc averages 1.0 out of 5 from 1 ratings, while RadexM averages 4.8 from 19 ratings.

### Do Decay calc or RadexM have ads?

Neither Decay calc nor RadexM shows ads.

### Which is updated more often, Decay calc or RadexM?

Decay calc ships an update every 3 months, and RadexM every 3 weeks. Most recently, Decay calc was updated on October 8, 2026 and RadexM on October 20, 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.*