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 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

What’s New

Version 7.3

Picking a racquet will automatically pick the string used last time.

Ratings and Reviews

4.7 out of 5
114 Ratings
114 Ratings
Switch God ,

Best Thing so Far

To date there is not an accurate device to measure string tension once the frame is off the machine.

This app is closest thing to a real solution. Based on good science this will give excellent data on RELATIVE tension. Meaning you can now track tension loss over time as well as compare the sticks in your bag before you step on the court.

The one caveat is that it does not come close to calculating absolute tension. I obtained wildly different tension numbers compared to "at time of stringing" tension. As much as 10-15 pounds off. But for measuring changes over time this app is the best thing out there!

Justin56537 ,

Bogus. Save your money

Doesn’t work plain and simple. I knew better. Just a toy.

Stringalong ,

It is what it is.

I got it yesterday, and tried it on several racquets I had to string. It does a passable job. My problem with this type of thing is it measures tension, in lbs. or kgs. As such, there will always be discrepancies of a number of units. What you are looking for when you measure a string job is consistency, or the drop in measurement from when it was first strung. Such metrics are better stated in units that have no particular relationship to units of measurement.

Since there are literally hundreds of strings on the market, it is possible, even probable that there is no linear information for the string you are using. Granted, you can get close with the information available, there will be variations, however slight, which will give a somewhat false reading.

The best way to use this app is get a measurement, regardless of variables and use that number to determine consistency between racquets strung at the same time or between string jobs on the same frame. You can then check unit change over time and how much playing.

One more thing; there will be differences of measurement between frames that are supposed to be exactly the same. This can be due to stiffness in the head, etc. so one can never be sure the measurements will be exactly the same, regardless of who strings the racquet.

Vince Chiarelli, MRT, PTR
String Along With Vince
Largo, Florida


Sten Kaiser
5.9 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
© Kaiser&Kaiser
In-App Purchases
  1. Stiffness Calculator $0.99


  • Family Sharing

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

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