# NuklidCalc vs IS RT

The clearest difference is update cadence: IS RT at every 5 months against NuklidCalc's every 12 months. NuklidCalc's advantage is iOS requirement (13.0 vs 15.6). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

NuklidCalc ships an update every 12 months, IS RT every 5 months. The most recent releases landed on September 9, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | NuklidCalc | IS RT |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 5 months** |
| Size | 15 MB | 28 MB |
| Requires iOS | **13.0** | 15.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Bundesamt für Gesundheit BAG](https://appshunter.io/developer/557143322) | [Institut de Soudure](https://appshunter.io/developer/1735474226) |

## What reviewers say

### NuklidCalc

[App page](https://appshunter.io/ios/app/nuklidcalc/id6463144495)

**Features:** macOS Compatibility

**In-app purchases:** none


### IS RT

[App page](https://appshunter.io/ios/app/is-rt/id6479296879)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is NuklidCalc free?

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

### Is IS RT free?

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

### Do NuklidCalc or IS RT have ads?

Neither NuklidCalc nor IS RT shows ads.

### Which is updated more often, NuklidCalc or IS RT?

NuklidCalc ships an update every 12 months, and IS RT every 5 months. Most recently, NuklidCalc was updated on September 9, 2026 and IS RT on September 17, 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.*