# Napier's Bones Simulation vs SISO Calculator

The clearest difference is price: SISO Calculator at Free against Napier's Bones Simulation's $1.99. SISO Calculator also leads on update cadence (every 5 weeks vs every 25 months). Napier's Bones Simulation's advantage is iOS requirement (12.0 vs 14.0). On ads, in-app purchases and device support there is nothing between them.

SISO Calculator is free to download; Napier's Bones Simulation costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Napier's Bones Simulation ships an update every 25 months, SISO Calculator every 5 weeks. The most recent releases landed on October 26, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | Napier's Bones Simulation | SISO Calculator |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Rating | — | **[5.0 (3 ratings)](https://appshunter.io/ios/app/siso-calculator/id1548141101/reviews)** |
| Number of ratings | — | **3** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 25 months | **Every 5 weeks** |
| Monetization | — | Free |
| Size | 29 MB | 4 MB |
| Requires iOS | **12.0** | 14.0 |
| Devices | **iPhone, iPad, iPod, Apple TV** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ventura Educational Systems](https://appshunter.io/developer/371324172) | [Deft Dynamics](https://appshunter.io/developer/1288783778) |

## What reviewers say

### Napier's Bones Simulation

[App page](https://appshunter.io/ios/app/napiers-bones-simulation/id1093899282)

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

**In-app purchases:** none


### SISO Calculator

[App page](https://appshunter.io/ios/app/siso-calculator/id1548141101)

This app helps engineers and students understand System Dynamics and Controls. It offers an intuitive interface to quickly analyze controller and plant interactions in both time and frequency domains.

**Highlights:** System Dynamics analysis, Controls engineering, Intuitive interface, Time domain analysis, Frequency domain analysis, Controller interaction visualization

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Napier's Bones Simulation free?

Napier's Bones Simulation costs $1.99, with no in-app purchases.

### Is SISO Calculator free?

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

### Do Napier's Bones Simulation or SISO Calculator have ads?

Neither Napier's Bones Simulation nor SISO Calculator shows ads.

### Which is updated more often, Napier's Bones Simulation or SISO Calculator?

Napier's Bones Simulation ships an update every 25 months, and SISO Calculator every 5 weeks. Most recently, Napier's Bones Simulation was updated on October 26, 2026 and SISO Calculator 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.*