Tennis ball pressure tester: no gauge needed.
You can't put a gauge in a tennis ball, but you can measure what its pressure does: the bounce. BallCheck listens to the ball bounce and tells you how much life it has left.
Or test a ball now in your browserA tennis ball has no valve, so a normal pressure gauge can't read it. A new pressurised ball holds about 10 to 13 psi above atmospheric pressure, and as that air leaks out, the ball bounces lower. Measuring the bounce, as the ITF's own drop test does, is the practical way to check a ball.
What pressure is inside a tennis ball?
The ITF says a new pressurised ball typically sits at 10 to 13 psi above atmospheric pressure, or 70 to 90 kPa. Pressurizer makers often quote about 14 psi, but the ITF figure is the one to trust.
Pressureless balls are different. Their air is at atmospheric pressure and the bounce comes from a thicker rubber core. The rules allow no more than 7 kPa (1 psi) inside them.
Why bounce is the real test
The official approval test does not open the ball. The ITF drops it from 254 cm (100 in) onto a granite block and measures the rebound. A new Type 2 ball must come back 135 to 147 cm.
Once a can is opened, air slowly leaks out through the rubber, and play speeds this up. Less pressure means a lower bounce, so the bounce shows what the pressure is doing.
| Ball | Rebound from 254 cm |
|---|---|
| Type 1 (fast) | 138 to 151 cm |
| Type 2 (medium) | 135 to 147 cm |
| Type 3 (slow) | 135 to 147 cm |
| High altitude | 122 to 135 cm |
Check a ball with your phone
- Lay your phone on the court, screen up, near where the ball will land.
- Hold the ball at net height and let go when the button turns green.
- BallCheck times every bounce by sound, scores the ball from 0 to 100 against a new one and tells you to keep, pressurize or retire it.
What a low score means
A low score means the ball has lost bounce, usually from pressure loss over time plus wear. A pressurizer may help a ball that has only lost some pressure. No independent published test of pressurizers was found, so test the ball again after a night in one.
A pressurizer can't fix worn felt, and it does nothing for a pressureless ball.
Questions
Can you measure tennis ball pressure with a gauge?
Not without damaging the ball. A tennis ball is a sealed rubber core with no valve, so there is nowhere to attach a gauge. Testing the bounce is the practical alternative.
What psi is a new tennis ball?
About 10 to 13 psi above atmospheric pressure, according to the ITF. That is about 70 to 90 kPa.
How accurate is a phone bounce test?
Each result is an estimate from the sound of the bounces, not a lab measurement. A quiet court and a clean drop give the best results, and comparing with a new ball on the same court removes most of the difference between surfaces.
Do pressurizers restore pressure?
They hold air around the balls so less leaks out, and some makers say they push air back in. No independent published test was found, so the best check is to test your balls before and after.
Sources
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