iPhone Screenshots


The best turntable RPM speed and accuracy testing mobile app available.

See the RPM speed variations, wow/flutter, of your turntable in real time graphics like you've never seen before.

There are many ways of testing the average RPM of your turntable, some turntables even have this built in, however there is no other practical way of showing the wow/flutter variation over time than RPM. The average RPM may look great however a large wow/flutter will make the sound terrible, RPM will help you identify the problem and visualise improvements you make.

Test the RPM and wow/flutter accuracy of your turntable, whether 16, 33 1/3, 45, or 78.

Now with the Worldwide RPM Turntable Accuracy Database you can research what other RPM users are finding out about their turntable's accuracy and what they think of them, + Stats of the most popular TT makes & models

● RPM is proud to be recommended by Rega Research Ltd, makers of some of the best turntables in the world.
● Great review by top tech vlogger Techmoan on Youtube
● Used in high end TT reviews in Stereophile magazine

Save all your rpm tests in My History for reviewing or sharing later.

RPM uses the gyroscope in your iPhone to determine the rotation speed of your turntable, automatically determines which speed setting you're on, and reports how accurate it is.

Simply place your iPhone flat over the centre of the turntable platter. As the iPhone rotates the display will remain stationary from your perspective for easy reading.

The UNIQUE feature of RPM is that it shows a scrolling graph of the rpm accuracy variation over time, this shows wow/flutter effects, especially those associated with the turntable not being level, belt wear, etc. You can even detect the small drag caused by the stylus resting in the grooves.

You can even visualise wow and flutter variations plotted actually around the vinyl centre to show a heat map of exactly where in the turntable rotation the inaccuracies occur.

For Upgraders the history graph parameters can be customised to:
- Set the moving average sample size.
- Accuracy at which to turn the rpm circle sold green.
- Set a duration after which the display updates will freeze so they can continue to be read after the turntable is stopped, this is also required to save sessions to History and upload to the World TT DB
- detect and graph 16, 45, & 78 records.

Calibration Mode is here! (Upgraders only plus not on iPod as compass required)
The RPM realtime display is reliant on the iPhones gyroscope accuracy, which is normally very accurate, if you suspect yours isn't quite right then you can now use Calibration Mode to auto test and then apply any necessary correction in real time.
This auto calibration uses the compass to count the turntable revolutions, if you have an older iPhone (not iPhone 6S or newer) then this may be unreliable, in this case you can still add your own multiplier if you have done an independent calibration.
Extensive testing means we're now confident that using RPM can help you setup your turntable to be within 0.1% of its target RPM, assuming your turntable can be adjusted and is itself stable within that tolerance of course.
Use 33 1/3 rpm for auto-calibration as at 45 and 78 rpm the compass simply won't be able to keep up.
Note that calibration isn't normally required, and that only uncalibrated sessions may be uploaded to the World TT DB to ensure all data is comparable.

Now with the World RPM Turntable Performance Database, accepting submissions from RPM users worldwide to build the ultimate resource for researching the most accurate turntables out there. Upgrade to join in and upload your own TT data, go to Settings and make sure you have the Freeze time set then do an RPM session as normal. At the end of the time you will can name your session after which you will have the option to upload it to the World DB. You can always upload from History later too.

Download for free and give it a try.

What’s New

Version 5.5

Additional onscreen info clarifying how many tests remain for trial users.

Ratings and Reviews

4.4 out of 5
1.6K Ratings

1.6K Ratings

Miljen ,


Minor update to my previous review, and back from 5 to 4 star. I can’t understand why are variations in speed measurements between devices so great? My iPhone 8 plus show 33,40 and iPhone SE 33,31 rpm, while strobe dots on my Technics 1210 are spot on (should be 33,33). When I slow turntable a bit, so that app measures 33,33 it is clearly slow which can be seen just by observing strobe dots on the platter. Wow/flutter is ok, very low measurements ... Could the app be more precise, or is it up to the phones and OS-es?

Developer Response ,

Update: There will undoubtedly be some variation between devices due to the tolerance of the gyroscopes for which there is nothing an app can do. If you are certain that your gyro is out then you can use the calibration feature in settings to apply a fix factor to match whatever calibration device you have used, then RPM will be able to be used as is from then on.
Thanks for the 5* upgrade!!
Update: Hi Miljen, RPM is indeed calculating the w/f as the max % deviation from the average rpm. I believe the IEC spec is primarily regarding the test tone method where it applies a weighting curve to the frequency response variation, in contrast rpm is unweighted. I do know that Rega turntables use a laser etched disc and optical sensor to measure speed and w/f. There is apparently a wide range of methods amongst tt manufacturers and no strict definition of what their w/f figures represent.
Regarding the precision of rpm, my target is that rpm will enable you to setup a TT to within 0.1% of the target, i.e., 33.30-33.37, my tests indicate this is achievable, however as Apple doesn't publish the tolerance of the iPhone gyroscope I am unable to be more specific. Your measurements are well within this tolerance variation which is a good sign. I hope that helps.
Hi Miljen,
Thanks for your feedback - the screenshots aren't indicative of a 'good' turntable deliberately to show the functionality clearer. I agree that ideally you would want the w/f to be below 0.3%
If you have any suggestions for improvements please let me know directly, I'd love to earn that 5th star!

Bradbort ,

Nice, but let it run for a bit

This app is good, although I highly recommend running in calibration mode first. Before I did that on a rega rp3, it was reading way faster than the strobe disk, but once auto calibrated it was quite close. This is with an iPhone XR.

I’m still a bit confused about wow and flutter and the circular trace it does. My sense is that it it showing unevenness in rotation and platter flatness, but for wow and flutter the relevant thing is what is happening where the needle touches the record. I’m, not sure if this w&F measure is comparable to what other folks measure. I did take heart, though, that my W&F readings were generally around .2, which seems to be about what most turntables in the database show...but I have no idea if other TT measurement systems would come up with the same number.

Cr4shMyCar ,

Good, but trial is way too limited and the full version costs way too much

This app is pretty good, as far as I can tell. It’s really easy to use and doesn’t require as much effort as a stroboscope; just put your phone on a roll of tape above your turntable’s spindle and go. However, it’s extremely limited on the free version, with only 10 tests for 33 RPM and, confusingly, no way to calibrate the app. Like another reviewer said, 10 tests is just enough to potentially get you into trouble if you don’t know what you’re doing. I have no qualms with paying for a good app, but 15 dollars for the full version is way too much for an app I’d rarely use. If you aren’t constantly adjusting the speed on turntables, just print out a stroboscope disk and get a stroboscope app. It takes a little more effort but it’s completely free.

App Privacy

The developer, Philip Broder, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Identifiers
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You Might Also Like