# PRODEOS vs Sigma Notepad Calculator

The clearest difference is in-app purchases: PRODEOS at none against Sigma Notepad Calculator's 3. PRODEOS also leads on device support (3 vs 1) and iOS requirement (12.2 vs 17.0). Sigma Notepad Calculator's advantage is ads (none vs shown). On price and update cadence there is nothing between them.

Both are free to download. Sigma Notepad Calculator sells 3 in-app purchases, starting at $1.99 per month. PRODEOS asks for nothing beyond the download.

PRODEOS ships an update every 3 weeks, Sigma Notepad Calculator every 2 weeks. The most recent releases landed on October 27, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | PRODEOS | Sigma Notepad Calculator |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Size | 102 MB | 18 MB |
| Requires iOS | **12.2** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Prodeos](https://appshunter.io/developer/1656000355) | [Soules Studio Ltd](https://appshunter.io/developer/1883253392) |

## What reviewers say

### PRODEOS

[App page](https://appshunter.io/ios/app/prodeos/id6737811643)

**Features:** macOS Compatibility

**In-app purchases:** none


### Sigma Notepad Calculator

[App page](https://appshunter.io/ios/app/sigma-notepad-calculator/id6768903761)

**Features:** Family Sharing

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $1.99 | per month |
| Annual | $14.99 | per year |
| Lifetime | $29.99 | one-time |


## Frequently asked questions

### Is PRODEOS free?

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

### Is Sigma Notepad Calculator free?

Sigma Notepad Calculator is free to download, with in-app purchases available.

### Do PRODEOS or Sigma Notepad Calculator have ads?

PRODEOS shows ads; Sigma Notepad Calculator does not.

### Which is updated more often, PRODEOS or Sigma Notepad Calculator?

PRODEOS ships an update every 3 weeks, and Sigma Notepad Calculator every 2 weeks. Most recently, PRODEOS was updated on October 27, 2026 and Sigma Notepad Calculator on October 31, 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.*