Stop guessing. Start measuring. Your strings are losing tension right now - and you can't feel it. One tap reveals the truth. String Tension AI shows you the true tension
Know exactly when your strings need replacing — before you feel it on court.
String Tension AI turns your iPhone's microphone into a precision string tension meter. Tap your stringbed, and the app instantly analyzes the sound to calculate your current tension. Track how your strings lose tension over time and get personalized recommendations for your next restring.
HOW IT WORKS
1. Tap your racquet strings near the microphone
2. The app analyzes the sound and calculates tension
3. Track changes over time and know when to restring
No external devices needed — just your iPhone.
MEASURE WITH CONFIDENCE
• Real-time quality coaching guides you to better readings
• Calibrate with a known reference tension for maximum accuracy
• Quality scoring ensures reliable, consistent measurements
TRACK TENSION OVER TIME
• Visual tension decay charts show exactly how strings lose tension
• Smart restring recommendations based on your actual data
• Set personal tension targets with alerts when strings fall outside range
• Compare performance across different racquets side by side
PERSONALIZED RECOMMENDATIONS
• Tension Advisor suggests your optimal stringing tension
• "What If" scenarios for different conditions and playing styles
• String recommendations matched to your playstyle profile
• Hybrid string builder finds your perfect main/cross combination
YOUR COMPLETE STRING TOOLKIT
• Database of 200+ tennis strings with detailed characteristics
• Pro player string and racquet setups from the ATP, WTA, and Legends tours
• Cost tracking and annual budget management for restringing
• Restring history and analysis across all your racquets
• String wishlist to plan what to try next
PLAYING SESSION TRACKER
• Log playing time with intensity tracking
• Weekly streaks, goals, and 38 unlockable milestones
• See how playing volume affects your string tension
BUILT FOR SERIOUS PLAYERS
• Unlimited free measurements — no paywall on core features
• iCloud sync keeps your data across all your devices
• Export detailed PDF and CSV reports
• Send string job reports directly to your stringer
FREE VS PRO
Free: Unlimited measurements, 1 racquet, quality coaching, calibration, session tracking, goals, fun facts, pro player databases
PRO: Unlimited racquets, full analytics and decay charts, tension advisor, string recommendations, hybrid builder, cost analytics, detailed playing stats, milestones, iCloud sync, PDF/CSV export
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Download String Tension AI now and take control of your string tension today.
Terms of Use: https://stringtensionai.com/terms/
Privacy Policy: https://stringtensionai.com/privacy/
I’ve been using this for one month now and it's become part of my routine before matches. You just tap the strings and get a reading. What surprised me is how consistent the readings are when I tracked them over time. I like the chart readings and trends. I use Luxilon Alu Power and those strings lose tension fast, so being able to actually see the drop over a week or two is really useful for knowing when my strings are dead and impacting my game. After getting my racquet restrung I calibrated it in the app and the absolute tension numbers lined up pretty well too. There's also a section where you can see what strings and racquets the pros use which is fun to browse. Can't believe this is free honestly. Wish I found it earlier.
Version 2.14 improves protected-data recovery after device lock, strengthens manual backup behavior from the persistence-error screen, and keeps live-store backup safety boundaries intact.
Plus performance improvements and bug fixes.
Version 2.14
The developer, Trader Prosperity LLC, 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:
Usage Data
Diagnostics
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Seller
Trader Prosperity LLC
Size
24.1 MB
Category
Sports
Compatibility
Requires iOS 17.0 or later.
iPhone Requires iOS 17.0 or later.
Mac Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
