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This page explains what governing bodies, standards bodies and researchers publish. It is not a substitute for lessons from a qualified coach or for medical advice.
The rule: approved balls only in tournaments
A note to Rule 3 of the ITF Rules of Tennis 2026 says that any ball used in a tournament played under the Rules must be named on the official ITF list of approved balls. Rule 3 also requires event organisers to announce in advance how many balls are in play (2, 3, 4 or 6) and any ball-change policy. If a ball breaks during a point, the point is replayed; a ball that is merely soft at the end of a point does not bring a replay (Rule 3 and Case 1).
Appendix I requires a uniform fabric cover on every ball except the Stage 3 (Red) foam ball, and any seams must be stitchless. The ITF's 2026 amendments did not change Appendix I.
The four adult ball types (Appendix I(b))
All four types weigh 56.0 to 59.4 g and are white or yellow. Forward deformation is 0.56 to 0.74 cm for all four.
| Type | Size | Rebound | Return deformation |
|---|---|---|---|
| Type 1 (fast) | 6.54 to 6.86 cm | 138 to 151 cm | 0.74 to 1.08 cm |
| Type 2 (medium) | 6.54 to 6.86 cm | 135 to 147 cm | 0.80 to 1.08 cm |
| Type 3 (slow) | 7.00 to 7.30 cm | 135 to 147 cm | 0.80 to 1.08 cm |
| High Altitude | 6.54 to 6.86 cm | 122 to 135 cm | 0.80 to 1.08 cm |
Deformation is the average of one reading on each of three perpendicular axes, and no two readings may be more than 0.08 cm apart. One small inconsistency: the 2026 rule book gives the Type 1 rebound in inches as 54 to 60, while the ITF's 2026 approval procedures reproduce the same rule as 53 to 60. The metric figure is the same in both, and the rule book says SI units take precedence.
Which ball for which court, and altitude
- Appendix I Case 1 says Type 1 (fast) balls are intended for slow-pace courts, Type 2 (medium) for medium-slow, medium and medium-fast courts, and Type 3 (slow) for fast courts. The pace categories are on court surfaces and pace.
- Type 2 balls may be pressurised or pressureless. A pressureless ball, with internal pressure of no more than 7 kPa (1 psi), may be used above 1,219 m (4,000 ft) if it has been acclimatised for 60 days or more at the tournament's altitude.
- Type 3 is also recommended for play above 1,219 m on any surface. The High Altitude ball is pressurised and is specified only for play above 1,219 m.
Durability (Appendix I(c))
After a laboratory test that simulates nine games of play, a ball may change by at most 0.4 g in mass, 4.0 cm in rebound, 0.08 cm in forward deformation and 0.10 cm in return deformation.
Stage balls for 10 and under (Appendix I(d))
Only these four balls may be used in 10 and under competition.
| Ball | Mass | Size | Rebound | Colour |
|---|---|---|---|---|
| Stage 3 (Red) foam | 25.0 to 43.0 g | 8.00 to 9.00 cm | 85 to 105 cm | Any |
| Stage 3 (Red) standard | 36.0 to 49.0 g | 7.00 to 8.00 cm | 90 to 105 cm | Red and yellow, or yellow with a red dot |
| Stage 2 (Orange) | 36.0 to 46.9 g | 6.00 to 6.86 cm | 105 to 120 cm | Orange and yellow, or yellow with an orange dot |
| Stage 1 (Green) | 47.0 to 51.5 g | 6.30 to 6.86 cm | 120 to 135 cm | Yellow with a green dot |
The rule book also gives forward deformation for the Orange ball (1.40 to 1.65 cm) and the Green ball (0.80 to 1.05 cm). The Green ball may be used at all levels of competitive play except world-ranking professional events, the Davis Cup and Billie Jean King Cup, Olympic and Paralympic tennis, ITF World Tennis Tour men's, women's and junior events, the ITF World Tennis Masters Tour and the ITF Wheelchair Tennis Tour. National associations decide whether it is used in their own national events.
How a ball gets on the ITF list (2026 procedures)
The ITF's document "Procedures for obtaining 2026 ITF Approval of Tennis Balls" (reference E97-010 rev. 25, issued August 2025) sets out the programme. It says ITF Approval means only that a ball was found to conform to the current Rules of Tennis and implies no other approval or endorsement.
- Who tests: only the ITF Technical Centre in London. National associations cannot approve balls on the ITF's behalf. Applications go through the online ITF TennisNET Portal.
- What is tested: rebound, mass, size, deformation and durability against Appendix I, plus visual and construction checks such as colour, stitchless seams and the fabric cover. Balls that crack or break in testing may be failed.
- Sample sizes: for standard and Stage 1 balls, 72 are submitted and 24 tested at random; for Stage 3 (Red) and Stage 2 (Orange) balls, 36 are submitted and 12 tested.
- The list: the 2026 list was to appear on the ITF website from 1 January 2026, showing each ball's name as printed on its packaging. The list itself could not be read for this site, so no count is given.
- Assimilation: a ball identical in core, cover and adhesive to an approved ball, but sold by the same company under another brand name or packaging, can be approved without testing. A different company's ball cannot.
- Markings: no more than two decals or stamps on the ball; a logo no taller than 32 mm, no wider than 52 mm and covering no more than 22 percent of the ball's face. The "ITF Approved" logo may appear on packaging but not on the ball.
- Refusals: approval is refused where the ball's markings, packaging or branding promote tobacco, hard liquor, betting, political activity or terrorism, or falsely suggest an official tournament ball.
Market testing and removal
The ITF also samples approved balls from the market worldwide, working with the Grand Slams, the ATP and the WTA, whose tournament balls may be tested. In a 12-ball sample, 2 or 3 failures bring a warning letter and 4 or more count towards removal; in a 24-ball sample the thresholds are 3 to 7 and 8 or more. Failures meeting the removal criteria across samples totalling at least 72 balls within 12 months bring a "yellow card" and a 12-month notice period. A second yellow card within the following 12 months can bring a "red card": ITF Approval is withdrawn for 12 months from that ball and from any balls assimilated to it. Balls made more than 12 months before testing are left out of removal assessments if the packaging carries production date codes.