Tennis ball types and the ITF rebound test
The ITF approves four kinds of adult tennis ball. Type 1 (fast) is for slow courts like clay, Type 2 (medium) for most hard courts, Type 3 (slow, slightly larger) for fast courts like grass, and a high altitude ball for play above 1,219 m. Each must bounce back within a set range when dropped from 254 cm onto granite.
The four ball types
All types weigh 56.0 to 59.4 g.
| Type | Best for | Size | Rebound from 254 cm |
|---|---|---|---|
| Type 1, fast | Slow courts (most clay) | 6.54 to 6.86 cm | 138 to 151 cm |
| Type 2, medium | Medium courts (most hard courts) | 6.54 to 6.86 cm | 135 to 147 cm |
| Type 3, slow | Fast courts (most grass) | 7.00 to 7.30 cm | 135 to 147 cm |
| High altitude | Above 1,219 m (4,000 ft) | 6.54 to 6.86 cm | 122 to 135 cm |
How the ITF tests a ball
Balls are stored for 24 hours at 20 °C and 60% humidity and squeezed first so every ball starts the same way. Each one is dropped from 254 cm onto a smooth granite block and the rebound is measured on video.
A separate durability test simulates nine games of play, with 20 hard impacts and two minutes in an abrasion box. Afterwards the rebound may change by no more than 4 cm.
Pressurised and pressureless balls
Most balls are pressurised to about 10 to 13 psi above the air outside. They feel lively but lose pressure once the can is open.
Pressureless balls are at normal air pressure, with a thicker rubber core doing the work. The ITF allows them as Type 2 balls if their internal pressure is no more than 1 psi above the air outside. They last longer and are common for practice and ball machines.
Heat and altitude
Heat makes the rubber livelier and the ball bounces higher, which is why the ITF tests at a fixed temperature. Thin air at altitude does the same: a Wilson engineer told the WTA that a regular ball at about 4,000 ft bounces about three inches higher. That is what high altitude balls are for.
BallCheck compares your ball with a new ball on the same court type, which takes most of the court out of the result. For the fairest comparison, test balls in similar conditions.
Questions
Which tennis ball type is most common?
Type 2 (medium pace). Most balls sold for hard court play are Type 2.
Are kids' balls tested the same way?
Yes, with lower ranges: green (stage 1) 120 to 135 cm, orange (stage 2) 105 to 120 cm and red (stage 3) 85 to 105 cm.
Does BallCheck use the ITF numbers?
Yes. Premium shows an estimated official test rebound for every ball, placed on the ITF range for that ball type.
Sources
- ITF Rules of Tennis 2026, Appendix I: The Ball
- ITF: Ball Approval Tests
- ITF 2026 Ball Approval Procedures
- WTA: Why high altitude tennis balls will play a big role in this year's WTA Finals
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