# XraySource vs The Formula Calculator

The clearest difference is update cadence: The Formula Calculator at every 5 days against XraySource's every 6 months. XraySource's advantage is iOS requirement (11.0 vs 15.0). 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.

XraySource ships an update every 6 months, The Formula Calculator every 5 days. The most recent releases landed on November 7, 2026 and November 10, 2026 respectively.

## The numbers

| Metric | XraySource | The Formula Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 5 days** |
| Monetization | — | Paid |
| Size | 61 MB | 9 MB |
| Requires iOS | **11.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Proto Manufacturing Limited](https://appshunter.io/developer/1521912683) | [Sidney Thom](https://appshunter.io/developer/6813788039) |

## What reviewers say

### XraySource

[App page](https://appshunter.io/ios/app/xraysource/id1521912681)

**In-app purchases:** none


### The Formula Calculator

[App page](https://appshunter.io/ios/app/the-formula-calculator/id6813788037)

This app serves as a comprehensive formula library and calculator, designed for tradespeople, engineers, and students. It offers over 200 formulas across various scientific disciplines, with automatic unit conversion and offline functionality.

**Highlights:** Extensive formula library (200+), Automatic unit conversion, Offline functionality, Searchable formulas and elements, Light and dark mode, Multi-language support

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is XraySource free?

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

### Is The Formula Calculator free?

The Formula Calculator is free to download, with no in-app purchases.

### Do XraySource or The Formula Calculator have ads?

Neither XraySource nor The Formula Calculator shows ads.

### Which is updated more often, XraySource or The Formula Calculator?

XraySource ships an update every 6 months, and The Formula Calculator every 5 days. Most recently, XraySource was updated on November 7, 2026 and The Formula Calculator on November 10, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*