# TennisTension — Measure Racquet's Tension

> Mobile app for measuring tennis racquet string tension using sound analysis. (iPhone/iPad app by Ivaylo Velichkov.)

- Source: https://appshunter.io/ios/app/tennistension/id1441997912 (this page in markdown: same URL + `.md`)
- Developer: [Ivaylo Velichkov](https://appshunter.io/developer/1688346812)
- Category: Health & Fitness, Sports
- Price: $8.99
- Rating: 5.00/5 from 2 App Store ratings
- Age rating: 4+
- Requires: iOS 18.0 · 6 MB
- Languages: English
- Released: 2019-02-20
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/tennistension/id1441997912/reviews.md

## What is TennisTension?

• TennisTension is the FIRST WORKING mobile app that instantly measures the momentous string tension of a tennis racquet with extreme  consistency and accuracy. We, the developers,  GUARANTEE  full satisfaction if you trust and buy TennisTension. The error of the measurements is less than 0.2 kg. Tracks the TENSION LOSS. It records and analyzes the ringing sound heard from the strings when they are hit with a stiff object (pen, pencil, another racquet, fingernails etc.).
• Systematically tested with different racquets and strings by players at different level of play - from beginners to ATP professionals.
• At ATP Sofia 2019 in January, 3 from the seeded players tested, approved and gave recommendations for improvements, which we implemented: string pattern, hybrid stringing, string opening size influence, noise disruptions. 
• If the user defines accurately all parameters of the tennis racquet and its string, then the error of the measurements will be less than 0.2 kg.
• Parameters to preset: head size; string pattern; main and cross string thicknesses and types; string opening size; stringing type. If some of them are not defined, the app will use the average default values or the last values the user put.

Use the "Calibration" to cope COMPLETELY with all specific characteristics of every racquet, string and stringing machine/stringer combination.

Instructions for use

- The user has to learn how to produce the proper ringing sound close (2 to 10 cm) and in front of the phone microphone. Find the microphone which uses single, very small hole either at the top or at the bottom of the phone.
- Remove the dampener - if you have. 
- Tap the racquet string very gently several times every 1 or 2 sec. with a stiff object. The best way is with pen or pencil, or use another racquet, fingernails, etc.
- While ringing, the resonating racquet string must stay 2 to 10 cm from the microphone, in front of it, especially in a noisier environment.
- To receive the exact momentous string tension, define all the necessary racquet and string parameters. If you don't know some of the them, default average values are taken for the calculations, or the last values that the user put it in. 
- TennisTension measures the average tension between main and cross strings of the racquet (for example, if a racquet is strung 25/24 kg, the measurement result will be 24.5 kg).
- String tensions of hybrid strings could be measured as well.
- The error of the measurement result is less than 0.2 kg.
- Calibration is provided, though it is not necessary to make it.

## Key features

- Instant string tension measurement
- High accuracy (<0.2 kg error)
- Tracks tension loss
- Analyzes string ringing sound
- Supports hybrid stringing
- Racquet parameter calibration


## Frequently asked questions about TennisTension

### What is TennisTension?

TennisTension is a mobile application that measures the string tension of a tennis racquet by analyzing the sound it makes when tapped. It offers high accuracy, with an error margin of less than 0.2 kg, and tracks tension loss over time.

### How does TennisTension measure string tension?

The app records and analyzes the ringing sound produced when racquet strings are tapped with a stiff object. By defining racquet and string parameters, it calculates the momentous string tension.

### What is the accuracy of TennisTension measurements?

When all racquet and string parameters are accurately defined by the user, the error of the measurements is less than 0.2 kg. This ensures consistent and reliable readings.

### Can TennisTension measure hybrid stringing?

Yes, TennisTension is capable of measuring the string tensions of hybrid string setups. It provides an average tension reading between main and cross strings.

### What devices does TennisTension support?

TennisTension is available for iPhone and iPad devices. It requires users to find and utilize their phone's microphone for sound analysis.

### How often is TennisTension updated?

The latest version of TennisTension is 1.7.3, which was last updated on June 27, 2025. This indicates active development and support for the application.

### What is the price of TennisTension?

TennisTension is a paid application, priced at $8.99. There are no in-app purchases or advertisements associated with this app.

### Does TennisTension have ads?

No, TennisTension does not contain advertisements. The application is a one-time purchase with no ads or in-app purchases.

## Version history (last 5 releases)

### 1.7.3 — 2025-06-27

Improved app accuracy and added 80 new string models.

### 1.7.2 — 2025-06-05

* Measurements accuracy improved
* For 1 year and free of charge unlimited usage of 3 new features included in the new app TennisTension Pro (the successor of TennisTension). That is the compensation for not supporting the original app TennisTension from now on: 
- A library with more than 130 different thoroughly examined most popular string models; 
- Saving in a list limitless number of racket/string configurations; 
- Measurements history section.

### 1.7.1 — 2020-12-04

Improving measurement accuracy.

### 1.6.0 — 2019-08-30

- small tweaks

### 1.5.0 — 2019-05-28

- UI changes
- bugfixes

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## More apps by Ivaylo Velichkov

- [TennisTension Pro](https://appshunter.io/ios/app/tennistension-pro/id6741165303)

All apps by Ivaylo Velichkov: https://appshunter.io/developer/1688346812

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*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.*