# Napier's Bones Simulation vs SlipStick

The clearest difference is update cadence: SlipStick at weekly against Napier's Bones Simulation's every 25 months. SlipStick also leads on price ($0.99 vs $1.99). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Napier's Bones Simulation costs $1.99 and SlipStick $0.99 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, SlipStick weekly. The most recent releases landed on September 23, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | Napier's Bones Simulation | SlipStick |
| --- | --- | --- |
| Price | $1.99 | **$0.99** |
| Rating | — | **[4.6 (9 ratings)](https://appshunter.io/ios/app/slipstick/id1523544516/reviews)** |
| Number of ratings | — | **9** |
| Positive reviews | — | 83.3% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 25 months | **Weekly** |
| Monetization | — | Paid |
| Size | 29 MB | 1 MB |
| Requires iOS | 12.0 | 12.0 |
| Devices | **iPhone, iPad, iPod, Apple TV** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ventura Educational Systems](https://appshunter.io/developer/371324172) | [Steve Glenner](https://appshunter.io/developer/1518671062) |

## 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


### SlipStick

[App page](https://appshunter.io/ios/app/slipstick/id1523544516)

This app is a fully functional digital reproduction of a classic engineering slide rule. It allows users to perform complex calculations like multiplication, division, logarithms, and trigonometry, just like the original manual tool.

**Highlights:** Virtual slide rule reproduction, Multiplication and division, Logarithm calculations, Trigonometry calculations, Classic engineering tool

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

**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 SlipStick free?

SlipStick costs $0.99, with no in-app purchases.

### Do Napier's Bones Simulation or SlipStick have ads?

Neither Napier's Bones Simulation nor SlipStick shows ads.

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

Napier's Bones Simulation ships an update every 25 months, and SlipStick weekly. Most recently, Napier's Bones Simulation was updated on September 23, 2026 and SlipStick on September 16, 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.*