# Pulley Calculator vs OpSense Task Checklist

The clearest difference is price: OpSense Task Checklist at Free against Pulley Calculator's $2.99. OpSense Task Checklist also leads on update cadence (every 2 months vs every 46 months). Pulley Calculator's advantage is iOS requirement (13 vs 16.6). On ads, in-app purchases and device support there is nothing between them.

OpSense Task Checklist is free to download; Pulley Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Pulley Calculator ships an update every 46 months, OpSense Task Checklist every 2 months. The most recent releases landed on September 18, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Pulley Calculator | OpSense Task Checklist |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[3.7 (34 ratings)](https://appshunter.io/ios/app/pulley-calculator/id1388205210/reviews)** | — |
| Number of ratings | **34** | — |
| Positive reviews | 25.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 46 months | **Every 2 months** |
| Monetization | Paid | — |
| Size | 1 MB | 7 MB |
| Requires iOS | **13** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nitrio](https://appshunter.io/developer/321121189) | [OPSENSE, INC.](https://appshunter.io/developer/1496817679) |

## What reviewers say

### Pulley Calculator

[App page](https://appshunter.io/ios/app/pulley-calculator/id1388205210)

This engineering calculator helps determine belt length, ratio, RPM, and belt speed for pulley systems. It offers instant calculations with copyable results and includes formulas for reference.

**Highlights:** Calculate Belt Length, Calculate Ratio, Calculate RPM, Calculate Belt Speed, Instant calculations, Copyable results, Includes formulas

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

**In-app purchases:** none


### OpSense Task Checklist

[App page](https://appshunter.io/ios/app/opsense-task-checklist/id1573614985)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Pulley Calculator free?

Pulley Calculator costs $2.99, with no in-app purchases.

### Is OpSense Task Checklist free?

OpSense Task Checklist is free to download, with no in-app purchases.

### Do Pulley Calculator or OpSense Task Checklist have ads?

Neither Pulley Calculator nor OpSense Task Checklist shows ads.

### Which is updated more often, Pulley Calculator or OpSense Task Checklist?

Pulley Calculator ships an update every 46 months, and OpSense Task Checklist every 2 months. Most recently, Pulley Calculator was updated on September 18, 2026 and OpSense Task Checklist on September 19, 2026.

---

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