# SoundRPM: Engine Tachometer — Estimate RPM by sound

> Estimate engine RPM from sound using your iPhone microphone. (iPhone/iPad app by 春城 贾.)

- Source: https://appshunter.io/ios/app/soundrpm-engine-tachometer/id6787410484 (this page in markdown: same URL + `.md`)
- Developer: [春城 贾](https://appshunter.io/developer/1501061855)
- Category: Utilities
- Price: Free with in-app purchases
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 9 MB
- Languages: American English, Chinese (Simplified, China)
- Released: 2026-07-06
- Data updated: 2026-08-31
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/soundrpm-engine-tachometer/id6787410484/reviews.md

## What is SoundRPM?

SoundRPM helps you estimate engine RPM using your iPhone microphone.

No wires. No OBD. No extra hardware.

Whether you are checking idle speed on a classic car, tuning a motorcycle, or working with a lawn mower, generator, chainsaw, or small engine, SoundRPM gives you a quick RPM estimate based on engine sound.

How it works:

1. Choose your engine type
2. Set cylinders and stroke type
3. Select your expected RPM range
4. Hold your iPhone near the engine or exhaust
5. Start listening and view the estimated RPM

Key features:

• Estimate engine RPM from sound
• Built for classic cars, motorcycles, and small engines
• Supports 2-stroke and 4-stroke configurations
• Choose cylinder count and RPM range
• Real-time RPM display
• Confidence level for every reading
• Stability indicator for idle checks
• Audio quality feedback
• Save measurement history
• No account required
• Audio is processed on your device

Use SoundRPM for:

• Classic car idle checks
• Motorcycle idle tuning
• Lawn mower RPM estimates
• Generator speed checks
• Chainsaw and small engine tuning
• DIY garage maintenance
• Before-and-after adjustment comparisons

SoundRPM is designed for stationary engine checks. Results may be affected by background noise, phone position, exhaust sound, engine configuration, and unstable throttle input.

Important safety note:

Do not use this app while driving. Keep your iPhone away from hot surfaces, belts, fans, pulleys, and other moving parts. SoundRPM provides estimated RPM readings only and is not a replacement for a professional tachometer or diagnostic tool.

Optional Lifetime Access is available in the app to unlock unlimited measurements and saved history.

What’s New:
Initial release of SoundRPM.

Estimate engine RPM from sound, choose engine presets, view confidence and stability, and save measurement history.

1. This service is a subscription based paid service, which means you will prepay for future subscription usage. You can currently choose to use this service on a quarterly basis. At the end of each subscription period, your subscription will automatically renew by default, unless you cancel the automatic renewal yourself or we cancel the service.
2. Unsubscribe: To cancel the renewal, please cancel at least 24 hours in advance. You can unsubscribe by opening System Settings, clicking on Apple ID, clicking on Subscription, selecting Premium, and then unsubscribing.
3. Restore purchase: If you receive a prompt saying "You have already subscribed to this project" during the payment process and confirm that you have completed the purchase before, you can click "Restore Purchase" in the upper right corner to restore the purchase.

Membership Service Agreement and Automatic Renewal Agreement:
https://gcn1s2rmayw3.feishu.cn/wiki/YgqKwPdJmiH0ulkF92kco1CznCg?from=from_copylink

Privacy Policy:
https://gcn1s2rmayw3.feishu.cn/wiki/SGBIwmUWCiPWoWktE5sclLRgnol?from=from_copylink

## Key features

- Estimate engine RPM from sound
- Supports 2-stroke and 4-stroke engines
- Choose cylinder count and RPM range
- Real-time RPM display
- Confidence level for readings
- Save measurement history

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Annual Member | $8.99 | per year |
| Monthly Member | $3.99 | per month |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Lifetime | $12.99 | one-time |



## Frequently asked questions about SoundRPM

### What is SoundRPM?

SoundRPM is a utility app that estimates engine RPM by analyzing the sound captured by your iPhone's microphone. It's designed for stationary engine checks on various types of engines.

### Does SoundRPM require any extra hardware?

No, SoundRPM does not require any wires, OBD connections, or additional hardware. It utilizes your iPhone's built-in microphone.

### What types of engines can SoundRPM be used with?

SoundRPM is built for classic cars, motorcycles, lawn mowers, generators, chainsaws, and other small engines. It supports both 2-stroke and 4-stroke configurations.

### How accurate are the RPM estimates from SoundRPM?

SoundRPM provides estimated RPM readings and includes a confidence level for each measurement. Results can be affected by background noise, phone position, and engine configuration.

### Can I save my measurements with SoundRPM?

Yes, SoundRPM allows you to save your measurement history. This feature is unlocked with the optional Lifetime Access purchase.

### Is SoundRPM safe to use?

Yes, but with important safety precautions. Do not use SoundRPM while driving and keep your iPhone away from hot surfaces and moving engine parts. It provides estimates and is not a replacement for professional tools.

### What are the subscription options for SoundRPM?

SoundRPM offers optional Lifetime Access for unlimited measurements and saved history. Subscription plans are available on a quarterly basis, with automatic renewal unless canceled at least 24 hours in advance.

### Does SoundRPM have ads?

No, SoundRPM does not contain advertisements. The app is free to download and use, with optional in-app purchases for enhanced features.

## Version history (last 5 releases)

### 1.9 — 2026-08-30

Further optimized the user experience

### 1.8 — 2026-08-19

Further optimized the user experience

### 1.7 — 2026-08-10

Further optimized the user experience

### 1.6 — 2026-08-09

Further optimized the user experience

### 1.5 — 2026-07-29

fix bugs

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All apps by 春城 贾: https://appshunter.io/developer/1501061855

## Related topics

[rpm car](https://appshunter.io/ios/topics/rpm-car) · [engine rpm](https://appshunter.io/ios/topics/engine-rpm) · [tachometer digital](https://appshunter.io/ios/topics/tachometer-digital) · [tachometer acoustic](https://appshunter.io/ios/topics/tachometer-acoustic) · [rpm meter](https://appshunter.io/ios/topics/rpm-meter)

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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 2026-08-31.*