RacquetTune - String Tension

Name: RacquetTune - String Tension
Rating: 4.6 (474 reviews)
Author: Sten Kaiser

by Sten Kaiser

iPhone · iPad

Active Last checked 31 Jul 2026

App Store ↗

Quick verdict

What it is: Store information collected; independent summary not yet available.
At a glance: $2.99

Categories and search queries

Official categories

Sports
Utilities

AppCorpus categories

Key functions

Function	Availability	Access	Scope	Evidence
Family Sharing	Yes	Unknown	App Store	Store published

Screens

No screenshots collected yet.

Pricing & paywalls

App Store

Price: $2.99

Last verified 31 Jul 2026

Ratings & reviews

App Store

4.6 474 ratings · App Store

5/5I 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

kayak4water · 31 Jul 2026
5/5String 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.

jdhdeudbdbd · 31 Jul 2026
5/5Great to understand tension
Great to understand how tension declines, not accurate but precise!. Keep notes on how it played and use the tension reported by the app as a reference. I use RPM Blast 17, pre-stretched 15 sec, strung at 55:53 and app reports 45.4, still very useful since these measurements are very consistent. I use this app now to keep a log of my string usage and tension. I recommend it!

joaocorreia · 31 Jul 2026
5/5Better 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.

Moradali · 31 Jul 2026
5/5great tool
been using it for years. great that it has note functions. I can know: when tension drops, How well I strung the racket and I can rate the setup for the future. Especially good for a nerd like me that tries a lot of different setups

Andyonehander · 31 Jul 2026

Privacy & accessibility

App Store

Privacy

Data Not Collected Developer declared

Accessibility

No accessibility labels collected yet.

Versions

App Store

4.8
Interface adaptions for iPhone 5s & 5c The ability to edit racquets and strings has been restored
5.0
- New design. - Much improved search, save, and contribution to the online string data base. - Display history while measuring (tap on the sound curve). - Sound frequency as a display option. - Improvements and fixes in the history curve - Other interface improvements. - Documentation improvements (more info buttons, Q&A in Guide etc) - Several minor updates and fixes
5.1
- Fixed an error in machine tension when saving tests. - Improved stability in Swingweight. - Other minor fixes and updates.
5.2
- Additional sound analyzis algorithm (FFT) to handle difficult racquets. - Microphone sensitivity can be set on newer iPhones to handle weak sounds (e.g. badminton racquets). - A default unit can be set in Tension. - Easier to select brand and string when searching the online database. - More consistent interface in Tension. - Translation in the info dialogs (Google translate, so sometimes a bit weird). - Other minor fixes and updates.
5.2.1
- Annoying update dialog removed. - iOS 5 fix. New in 5.2 - Additional sound analyzis algorithm (FFT) to handle difficult racquets. - Microphone sensitivity can be set on newer iPhones to handle weak sounds (e.g. badminton racquets). - A default unit can be set in Tension. - Easier to select brand and string when searching the online database. - More consistent interface in Tension. - Translation in the info dialogs (Google translate, so sometimes a bit weird). - Other minor fixes and updates.
5.3
- The string factor measurement has been improved for thinner strings (e.g. Badminton). - Sorting racquets in History. - Strange characters appearing in the racquet list in some languages has been fixed. - Other minor fixes.
5.4
- Interface improvements (better consistency) - iOS 8 adaptions - Stiffness in History graphs. - Frequency in the tension range setting. - Unit setting in the save dialog remembered - A number of minor fixes
5.4.1
Fixed a crash when deleting a row in History.
5.5
- The tension drop is displayed on the test page - A number of minor fixes
5.6
The Stiffness Calulator is now free to celebrate the 5:th annivesary of RacquetTune. Updates in 5.6: - Double tap on the sound graph to see the harmonics (can be useful for difficult racquets). - When sorting racquets 'Recent' now means 'recently used', not recently added as before. - Some minor fixes.
5.7
- Improvements in the sound analysis resulting in even more consistent results and fewer strikes. - Access to on line racquet data in SwingWeight. - iOS 9 compatibility. - Some minor fixes.
5.8
- Current racquet and string are displayed on the test page (tap on the sound curve). - Consistent use of decimal comma in relevant countries. - Several minor fixes.
6.0
- Racquet, string and test data can be saved to iCloud for easier backup and transfer to another device. - More string patterns in Stiffness. - Bug fixes in Swingweight. - Fixed the translate button in the Guide. - iOS 10 updates.
6.1
- Fixed the formatting of the exported testdata in countries with decimal point. - Fixed a problem with a frozen database that could occur while testing.
6.2
- Twistweight in the swingweight calculator. - The swingweight calculator can display changes as well as absolute values.
6.2.1
Fixed a problem in the tension display that could cause a crash on some devices.
6.3
- iOS 11 compatibility - Fixed a database conflict
7.0
This is a major update of RacquetTune that contains: - Better adaption to different screen sizes - New tension database - New swingweight database - Better handling of hybrid strings - Interface improvements - Much improved data export - A lot of smaller fixes and improvements
7.1
- The curve view in History has been restored and improved. - A 'broken string' setting in save tension. - 'Played hours' can be set as a decimal. - Stiffness is shown in the History detail view. - Fixed a problem with duplicated comments in History.
7.2
- A set up in History for configuring the display. - The tension drop in % can be displayed in the curve view. - A potential crash in the curve view has been fixed.
7.3
Picking a racquet will automatically pick the string used last time.
7.4
iOS 13 compatibility improvements (dark mode will come later).
7.5
- Easier to pick strings in the online DB. - A sound detection problem on some device has been improved/fixed .
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.
7.7 · 2 Apr 2026
This update from Apple will improve the functionality of this app. No new features are included. - Fixed the problem with detecting sound on iOS 26.4 and later. - Fixed an issue with contributing strings to the online database.

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Availability by market

Data quality & evidence

Page completeness: Live store listing
Last verified: 31 Jul 2026
Sources: App Store

Independent summary has not been published yet.
Screenshots: not yet collected

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GET /api/v3/apps/365729342

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          "title": "I must be doing it wrong",
          "body": "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",
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          "body": "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.",
          "author": "jdhdeudbdbd",
          "date": "31 Jul 2026"
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        {
          "rating": 5,
          "title": "Great to understand tension",
          "body": "Great to understand how tension declines, not accurate but precise!. Keep notes on how it played and use the tension reported by the app as a reference. I use RPM Blast 17, pre-stretched 15 sec, strung at 55:53 and app reports 45.4, still very useful since these measurements are very consistent. I use this app now to keep a log of my string usage and tension. I recommend it!",
          "author": "joaocorreia",
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        {
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          "date": "31 Jul 2026"
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