RacquetTune - String Tension 4+

Racquet optimization tools

Sten Kaiser

    • $2.99



Listen to your racquet and perfect your game!

RacquetTune ensures that your racquet is ideally suited to your style of play. Simple and straightforward to use, the app uses the sound generated by tapping the strings to calculate the tension with high accuracy. In addition, the interactive swingweight calculator aids in customizing your racquet to fit your own stroke pattern, while the stiffness calculator allows you to simulate different racquet configurations.

RacquetTune not only makes it easier to decide when it is time to restring, it is also an invaluable tool when testing different racquets and strings and in identifying which of your racquets is best suited for different types of games. RacquetTune also allows you to check whether your stringer is consistent in his work.
RacquetTune includes the following user-friendly tools:

Tension measurement
- Quickly determines the tension and stringbed stiffness.
- Able to detect changes in tension as small as 0.1 kg/0.2 lb.
- An accuracy indicator ensures results are consistent.
- Graphical presentation of sound waves helps you find the ideal way of tapping the strings.
- Settings can be customized to serve tennis, squash, racquetball and badminton racquets, respectively.
- View the tension history for each racquet as a list or a graph.
- Email a spreadsheet with test data.

Swingweight calculator
- Add as many weights as you wish to the frame.
- Move and change weights to visualize how swingweight, balance and sweet spot location are affected.
- Enter target values for the racquet and let RacquetTune distribute the weights automatically.

Stiffness calculator
- Simulate various racquet and string configurations
- Vary tension, string type and racquet head size.
- Shows load-displacement curves, stiffness and elastic energies
- Handles the large deformations encountered in actual play

View a demo video at racquettune.com

RacquetTune has been featured in tennis magazines in USA, Italy, France, Germany, Sweden and Norway.

"The app is very, very impressive. I get more tension diagnostic questions than just about anybody in the universe, so this is a very good thing to be able to recommend."
Jonathan Wolfe
US Racquet Stringers Association

Note, that the actual string tension in the racquet and the setting seen on a stringing machine are two different things and therefore incomparable - more information can be found at racquettune.com.

What’s New

Version 7.6

- All weights in swingweight can be removed with a long press on the +Weight button.
- A problem with uploading the database has been fixed.

Ratings and Reviews

4.7 out of 5
384 Ratings

384 Ratings

kayak4water ,

I must be doing it wrong

I restrung my racquet at 55#. This app said the tension was 40.2# right after I finished. I checked the string factor and ensured that I’d entered the correct values all the parameters (e.g. string pattern, racquet face size). I followed the measurement procedure to the letter.
I could believe a couple lb. change but 15? Nyet. The racquet plays like 50-55.
A Gamma String Tension Tester said the two center main strings were at 55# and the two center cross strings were at 39 and 40#.
Why are other users getting numbers close to the tension at which they strung?
Not even close for this app. Sorry

jdhdeudbdbd ,

String factor accuracy is crucial

Fantastic app. Incredibly useful to graph how the racket loses tension over time. Readings are very accurate. (note, if I’m stringing a poly, I can sometimes lose up to 10% by the time it’s off the stringer, then maybe another 10% over the next 48 hours) String factor accuracy is crucial, and the online database can be hit or miss, you’ll see lots of variation in there. You should measure this yourself to make sure it’s accurate, because it will greatly affect the reading. I use the weight method, and that’s worked out well for me so far.

Moradali ,

Better than I expected

I have had this App for a week now and the results have been much better than expected! I use it to find out how much tension drops after each playing session.

App Privacy

The developer, Sten Kaiser, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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