# IS RT vs WeldCalc Pro

The clearest difference is in-app purchases: IS RT at none against WeldCalc Pro's 3. IS RT also leads on iOS requirement (15.6 vs 17.0). WeldCalc Pro's advantage is update cadence (every 3 weeks vs every 5 months). On price, ads and device support there is nothing between them.

Both are free to download. WeldCalc Pro sells 3 in-app purchases, starting at $1.99 per 7 days. IS RT asks for nothing beyond the download.

IS RT ships an update every 5 months, WeldCalc Pro every 3 weeks. The most recent releases landed on November 4, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | IS RT | WeldCalc Pro |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 weeks** |
| Size | 28 MB | 21 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [Institut de Soudure](https://appshunter.io/developer/1735474226) | [Ersel Tarhan](https://appshunter.io/developer/1093545232) |

## What reviewers say

### IS RT

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

**Features:** macOS Compatibility

**In-app purchases:** none


### WeldCalc Pro

[App page](https://appshunter.io/ios/app/weldcalc-pro-welding-calc/id6759536437)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Premium | $1.99 | per 7 days |
| Annual Premium | $19.99 | per year |
| WeldCalc Pro Lifetime | $39.99 | one-time |


## Frequently asked questions

### Is IS RT free?

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

### Is WeldCalc Pro free?

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

### Do IS RT or WeldCalc Pro have ads?

Neither IS RT nor WeldCalc Pro shows ads.

### Which is updated more often, IS RT or WeldCalc Pro?

IS RT ships an update every 5 months, and WeldCalc Pro every 3 weeks. Most recently, IS RT was updated on November 4, 2026 and WeldCalc Pro on November 5, 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.*