# Pulley and Belt Calculator — Gear Ratio, RPM & Length

> Gear Ratio, RPM & Length (iPhone/iPad app by Vladislav Zhirnov.)

- Source: https://appshunter.io/ios/app/pulley-and-belt-calculator/id6757499533 (this page in markdown: same URL + `.md`)
- Developer: [Vladislav Zhirnov](https://appshunter.io/developer/1476188065)
- Category: Utilities, Productivity
- Price: $1.99
- Age rating: 4+
- Requires: iOS 16.6 · 3 MB
- Languages: Danish, Ukrainian, Russian, Croatian, Hungarian, Norwegian Bokmål, Hindi, Indonesian, Turkish, Hebrew and 22 more
- Released: 2026-01-10
- Data updated: 2026-08-24
- User reviews in markdown: https://appshunter.io/ios/app/pulley-and-belt-calculator/id6757499533/reviews.md

## What is Pulley and Belt Calculator?

Pulley & Belt Calculator instantly computes drive ratios, belt lengths, and pulley speeds (RPM) for both single and multi-stage belt drive systems. It takes the guesswork out of designing and tuning your mechanical projects. Designed for engineers, mechanics, and DIY makers, this app offers two dedicated calculation modes with rich visual diagrams to simplify complex pulley setups.

Key Features:

Two-Pulley Calculator: Calculate a two-pulley setup with ease. Input pulley diameters, center distance, and a known RPM to get the belt length, driven pulley RPM, speed ratio, and contact angles for your system.

Multi-Stage Calculator: Chain 2–4 pulley stages (multiple belts) to determine the overall gear ratio and final output RPM. Ideal for designing speed reductions or increases across several pulley sets. Includes a quick toggle for setting the initial driver on the bottom or top, accommodating both reduction and step-up scenarios.

Quick Adjust Tool: Fine-tune center distances effortlessly. This feature automatically equalizes the belt slack (gap) between pulleys on all stages for an optimal fit – especially useful in confined spaces or when you want uniform tension across belts.

Interactive Diagrams: Visualize your pulley system in action. The app provides animated, scaled diagrams of your belt drive, along with an RPM gauge, so you can see relative speeds and rotational motion in real time. This helps you intuitively understand the system’s behavior.

Export & Share: Save and share your results. With one tap, export a PDF report of your calculations – including inputs, results, and schematic diagrams – perfect for project documentation or collaboration. (For example, similar apps allow sharing results via text or email, and we’ve built this app to integrate seamless export for your convenience.)

User-Friendly & Offline: Enjoy a clean, ad-free experience. The interface is intuitive, with all inputs and results displayed clearly. All calculations run offline on your device (no internet required). Unit support is in metric (millimeters) for precise input; this caters to standard engineering measurements and ensures high accuracy in results.

Whether you’re a professional building industrial machinery or a hobbyist tuning an automotive belt drive, Pulley & Belt Calculator provides accurate results in seconds. It’s a must-have tool for anyone working with belt-driven systems – empowering you to design, optimize, and troubleshoot pulley setups with confidence and precision. Download now and take control of your pulley projects!

## Chart rankings

- #198 in Top Paid · Utilities (US App Store)


## Version history (last 1 release)

### 1.0 — 2026-01-10

No release notes.

## Apps similar to Pulley and Belt Calculator

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Pulley & Belt calculator](https://appshunter.io/ios/app/pulley-and-belt-calculator/id6470370055) | 1.3 (3) | $1.99 | Utilities |
| [Pulley Calculator](https://appshunter.io/ios/app/pulley-calculator/id1388205210) | 3.7 (34) | $2.99 | Utilities |
| [Miter Bend Layout Calc](https://appshunter.io/ios/app/miter-bend-layout-calc/id6753969543) | — | Free | Utilities |
| [Gear Simulation & Calculation](https://appshunter.io/ios/app/gear-simulation-and-calculation/id1618701429) | 4.3 (11) | $3.99 | Utilities |
| [HVAC Duct Sizer](https://appshunter.io/ios/app/hvac-duct-sizer/id317970395) | 2.9 (8) | $5.99 | Utilities |
| [TC-RTD Reference](https://appshunter.io/ios/app/tc-rtd-reference/id6504454500) | 5.0 (1) | $1.99 | Utilities |

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All apps by Vladislav Zhirnov: https://appshunter.io/developer/1476188065

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-24.*