SoundRPM: Engine Tachometer

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