# RPMmtr — RPM Tachometer based on Sound > Measures rotational speed (RPM) using sound analysis for engines and machinery. (iPhone/iPad app by Andreas Bartl.) - Source: https://appshunter.io/ios/app/rpmmtr/id1533839290 (this page in markdown: same URL + `.md`) - Developer: [Andreas Bartl](https://appshunter.io/developer/1533839292) - Category: Productivity, Business - Price: $1.99 - Rating: 1.38/5 from 8 App Store ratings · 10 written reviews indexed - Age rating: 4+ - Requires: iOS 14.4 · 1 MB - Languages: English - Released: 2021-02-07 - Data updated: 2026-06-10 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/rpmmtr/id1533839290/reviews.md ## What is RPMmtr? Engines, motors and rotating machinery generate periodic sound patterns. RPMmtr analyses those sound patterns to measure RPM (rotational speed) based on state-of-the-art signal processing technology. The result of this estimation is shown in three different views. The tachometer view displays the rotational speed at a glance. The color of the dent indicates how clear the measurement is. You can swipe the red ring control and improve the result by specifying the expected RPM range. The tracking view shows the evolution of the rotational speed over time. The accuracy of the measurement is indicated by the size and color of the circles. Experts can use the spectrogram view: the graph shows the frequency distribution of the sound. Small arrows show the rotational speed. Adjust the axes scaling by a swipe with one finger. Notice on usage: The app can estimate the correct rotational speed only in cases if the sound is very clear (i.e. the rotating device generates clear periodic sound patterns with one frequency) and there is no background noise. RPMmtr is for educational purposes only. We do not take responsibility for decisions taken by the reader based solely on the information provided in this app. ## Key features - Sound pattern analysis for RPM measurement - Tachometer view for at-a-glance speed - Tracking view for speed evolution over time - Spectrogram view for frequency distribution - Adjustable RPM range control - Accuracy indication through visual cues ## Recent user reviews (10 of 10) All indexed reviews: https://appshunter.io/ios/app/rpmmtr/id1533839290/reviews.md ### 1/5 — Don't get this app *2024-12-29* Doesn't work as advertised. Benchmarked against built in tach. Did not match at idle or under throttle. Always showed weak signal even when held against engine case. Tried on parallel twin 4-stroke and single cylinder 2-stroke ### 1/5 — Not worth it if it was free. *2024-10-16* App does not work different rpm every time the app is opened under identical conditions and the numbers are not remotely close. ### 1/5 — Don’t buy. Does Not Work. *2024-07-20* I tried everything to get this app to work, but it kept saying to hold it closer. I couldn’t have held it any closer. Simply doesn’t work. Luckily it’s not very expensive, but I should have thought to check the reviews before wasting a couple bucks 😔 ### 1/5 — Didn’t work as intended *2024-02-15* The app couldn’t pick up the sound of my Yamaha xvs650, despite being repetitive and loud. Put it right up to the exhaust at one point and still no dice. ### 1/5 — Complete rubbish *2023-08-15* Don’t waste one penny on this, complete waste of time. It’s just a rip off. I got the same RPMs when it was next to the engine, and when the engine was completely turned off, and in a very quiet environment. ### 1/5 — App Does Not Work *2022-11-15, version 1.5* This gauge does not work. Can’t tell the difference between voices, background sound or motors. ### 2/5 — Doesnt work on mr DR650 *2022-10-13* Maybe it doesnt work because its a single cylinder but I tried putting the phone next to the engine, next to the exhaust, on the seat, and I always get a message telling me phone is not close enough to the source. The concept is great, but the app just didn’t work for me. ### 1/5 — Doesn’t Work As advertised *2021-10-31, version 1.5* This app simply does not work as advertised. Even though it’s cheap, I wouldn’t recommend it! I tried using this app to measure the idle RPM’s on my single cylinder motorcycle so I can set the air/fuel screw correctly. No matter what settings I change it says that my bike is running around 5000+ RPMs at idle!! That’s simply not possible seeing my bike red lines at 8000 RPM! The developer commented on my last review saying they fixed some few things that should help but it did not!! I still feel like I completely wasted of money on this app because IT DOES NOT WORK CORRECTLY!!!! PLEASE FIX THIS APP SO IT WIRKS CORRECTLY!!!!!!!!!!!!! **Developer response:** Thanks for your feedback. We updated and improved the algorithm in the new version. Maybe it helps to solve your problems with the app. ### 2/5 — No adjustments for cylinders *2021-08-29, version 1.3.1* I was trying to use this for a motorcycle. There is no way to adjust for number of cylinders to get an accurate number. My assumption is it was counting each sound to get the number so I divided by two to get 1200 rpm at idle as it was reading 2400. **Developer response:** Thanks for the feedback. We added a setting for accounting for the harmonic order. I hope that helps with your problem. ### 3/5 — Seems to apply a correction factor? *2021-05-21, version 1.3.1* I like the function of this app but it seems to assume I am measuring a 4 cylinder engine and the output is divided by 4. Can you make a setting to adjust this? Actually I am trying to measure the vibration of some consumer electronics so I want 1:1 output. **Developer response:** Thank you for your feedback. We added a setting for accounting for the harmonic order. That should help for the 4 cylinder problem. For the consumer electronics problem: do you need to have the dominant vibration frequency? ## Frequently asked questions about RPMmtr ### What is RPMmtr? RPMmtr is a productivity app that measures rotational speed (RPM) by analyzing the sound patterns of engines and machinery. It provides various views to display this data for educational purposes. ### How accurate is RPMmtr? The accuracy of RPMmtr depends heavily on the clarity of the sound source and the absence of background noise. The app indicates measurement clarity and accuracy through visual cues in its different views. ### What devices does RPMmtr support? RPMmtr is supported on iPhone and iPod devices. It was last updated on October 20, 2021, with version 1.5. ### What is the price of RPMmtr? RPMmtr is a paid application, available for $1.99. There are no in-app purchases or advertisements mentioned for this app. ### What is the age rating for RPMmtr? RPMmtr has an age rating of 4+, making it suitable for a wide range of users. The app is intended for educational purposes. ### Does RPMmtr have ads? No, RPMmtr does not contain advertisements. The app is a paid download and does not feature any in-app ads. ### Can RPMmtr be used for professional diagnostics? RPMmtr is explicitly stated to be for educational purposes only. The developers do not take responsibility for decisions made based solely on the information provided by the app. ### How often is RPMmtr updated? RPMmtr was last updated on October 20, 2021, to version 1.5. The initial release date was February 7, 2021. ## Version history (last 5 releases) ### 1.5 — 2021-10-20 - Analysis quality warning - Predefined suggestions for RPM ranges - Correction factor for dominant harmonic order ### 1.3.1 — 2021-05-07 Bug fix ### 1.3 — 2021-05-02 - Bug fix ### 1.2 — 2021-02-10 Improved performance. ### 1.1 — 2021-02-08 Improved performance ## Apps similar to RPMmtr | App | Rating | Price | Category | | --- | --- | --- | --- | | [My Location Tracker](https://appshunter.io/ios/app/my-location-tracker/id6443891970) | 4.8 (29) | Free | Productivity | | [1440: countdown timer](https://appshunter.io/ios/app/1440-countdown-timer/id1324295186) | 4.8 (53) | Free | Productivity | | [LittleDo](https://appshunter.io/ios/app/littledo/id1578741546) | — | $0.99 | Productivity | | [Electronic Toolbox Pro](https://appshunter.io/ios/app/electronic-toolbox-pro/id339158729) | 4.7 (240) | $12.99 | Productivity | | [SheetSnapper](https://appshunter.io/ios/app/sheetsnapper/id1468216420) | 4.1 (15) | Free | Productivity | | [It's a widget](https://appshunter.io/ios/app/its-a-widget/id1533616730) | 1.0 (1) | Free | Productivity | --- *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 2026-06-10.*