Official Table Tennis Ball Specifications, Explained (ITTF)
The Laws of Table Tennis define the ball with a short list of numbers: diameter, weight, material, colour and finish. ITTF-approved balls must also pass further tests set out in the ITTF’s Technical Leaflet T3.
This page covers each specification, the two best-known changes to the ball (diameter in 2000, material in 2014), and what the ITTF leaflet actually says about star-style grade labels.
Short answer: The official ball is 40mm in diameter, weighs 2.7 grams, and is made of plastic in white or orange with a matt finish (Law 2.3). In the ITTF approval test (Technical Leaflet T3, 2014 version), balls must rebound 24 to 26cm when dropped from 30.5cm onto a standard steel block.
Table of Contents
Diameter: 40mm, Up From 38mm
The official diameter is 40mm, spherical (Law 2.3). The ball used to be 38mm: the larger ball replaced it in October 2000. Accounts of the change, such as the Wikipedia table tennis article, say the larger ball’s greater air resistance slowed the game and that the aim was to make the sport easier to follow as a televised spectator sport. These are secondary accounts, not an ITTF statement.
Weight: 2.7 Grams
The official weight is 2.7 grams (Law 2.3). In the ITTF approval test, T3 accepts any single ball between 2.67 and 2.77 grams, no more than 1 ball in the 24-ball sample may fall outside that range, and the sample mean must be between 2.69 and 2.76 grams.
Material: Plastic, Not Celluloid
The Laws now say the ball shall be made of plastic material (Law 2.3). They do not name a specific plastic, and the ITTF leaflet T3 states that the Laws do not prescribe the material. Plastic replaced celluloid at ITTF-sanctioned events from 1 July 2014, according to the ITTF announcement as reproduced by Paddle Palace (blog.paddlepalace.com, August 2014), which cites celluloid’s flammability, the cost of shipping it, and a dwindling supply of celluloid sheet. T3 also describes celluloid as unstable and flammable.
📊 Note: The celluloid-to-plastic transition is a separate event from the 38mm-to-40mm diameter change covered above. They happened at different times (2000 and 2014) and, going by the sources above, for different stated reasons.
Color: White or Orange, and Specifically Matt
Official balls are white or orange (Law 2.3). The Regulations also require the main colour of a player’s shirt, skirt or shorts, other than sleeves and the collar of a shirt, to be clearly different from the ball in use (Regulation 3.2.2).
The ball must also be matt (Law 2.3). The Laws do not say why. Reduced glare is the obvious practical reason, but that is general reasoning, not an ITTF statement.
The Bounce Test: a Precise, Measurable Standard
The bounce requirement is part of the ITTF approval test rather than the Laws themselves. Under Technical Leaflet T3 (2014 version, section B.7), all 24 balls in a test group must rebound to a height of not less than 240mm and not more than 260mm when dropped from 305mm onto a standard steel block, which is 24 to 26 centimeters from a 30.5 centimeter drop.
💡 Pro tip: A home drop test cannot confirm ITTF compliance, because the ITTF test uses a calibrated steel plate and camera measurement. At most, dropping a few balls from the same height onto a hard flat surface shows whether they differ noticeably from one another.
What the 2000 Diameter Change Changed
The Laws now specify a 40mm diameter and a 2.7 gram weight. How the larger ball changed play is described in general terms in secondary accounts (more air resistance, a slower game), not in ITTF-published measurements.
The 2014 Material Switch
T3 states the ITTF’s goal that balls of any material have the same good level of quality and stable properties. It also records that the approval specifications for non-celluloid balls were temporarily loosened for weight, bounce and hardness until 1 January 2016, after which the original specifications applied.
Why This Matters for Buying Practice Balls
The practical use of these specifications is checking a ball’s markings. Under T3, an approved ball’s stamp must carry the ITTF approval (the initials “ITTF”, “ITTF approved” or the ITTF logo), the brand name, “Made in” and the country, and “40+” for a non-celluloid ball, with no other text. Packaging must carry “40+” wording for non-celluloid balls and a date code. T3 also says the ITTF publishes a list of approved ball brands online. Price alone says nothing about whether a ball is approved.
- ✓Check that the ball’s stamp shows ITTF approval and “40+”, not just a star label
- ✓Remember the 24 to 26cm bounce rule is a lab test, not something you can confirm at home
- ✓Check the packaging for “40+” wording and a date code
- ✓Remember the ball’s color connects directly to the clothing color rule for competitive play
- ✕Assume a ball meets the full official specification just because the label says 40mm or 3-star
- ✕Treat a star label as proof of ITTF approval
- ✕Ignore the matt-finish requirement as a purely cosmetic detail
- ✕Assume every plastic ball is ITTF approved
The Short Version, Restated
The Laws define the ball as 40mm in diameter, 2.7 grams, and made of matt plastic in white or orange. The ITTF’s approval test adds further limits, including a 24 to 26cm rebound from a 30.5cm drop onto a steel block.
The two best-known changes to the specification are the diameter increase from 38mm to 40mm in October 2000 and the move from celluloid to plastic at ITTF-sanctioned events from 1 July 2014.
How Star Ratings Relate to These Specifications
Many ball boxes show a star grade. The ITTF leaflet T3 says very little about it: if the grade of the ball is indicated by a numbering system, no number higher than 3 may be used, for example “Three Star”. It does not say what each number means or how a 1-star ball differs from a 3-star ball, so any such tier meaning comes from the brand, not from the ITTF.
Because every ITTF-approved ball has to meet the approval criteria in T3 (the leaflet says all approved brands must meet all of them), the stamp and approval wording are the reliable signals, and the star number should be read as the brand’s own label.
The Full ITTF Certification Battery: Sphericity, Veer, and Hardness
The headline numbers above are what most players need. The ITTF’s leaflet T3 sets out several more tests that approved balls must pass, applied to test groups of 24 balls.
Sphericity is the roundness test. T3 measures the minimum and maximum diameter of each ball while rotating it about several axes, and the difference between the two is the lack of sphericity, which has an upper limit for any single ball and another for the sample mean. Check the current leaflet on ittf.com for the exact figures.
There is also a veer test. Each ball is rolled down a slight incline onto a flat surface and measured three times for how far it drifts from a straight centre line. A ball fails if it hits one of the side lines 175mm either side of the centre line, and no more than two balls in the sample may fail, meaning deviate twice by more than 175mm (T3, section B and B.9).
Hardness is measured by indentation at the ball’s poles, and the range depends on construction. For balls with a seam, T3 section B.10 gives a geometric mean pole hardness of 0.68 to 0.81mm for any ball. For balls without a seam, it gives 0.70 to 0.90mm.
Colour is measured too. T3 says ball colour is measured and calculated with the CIE Lab system, using a spectrophotometer, and compared with reference standards for white and orange.
Packaging is covered too. T3 says balls must be packaged appropriately, for example in paper or plastic boxes or in a blister pack, with “40+” wording for non-celluloid balls and a date or date code.
📊 Note: T3 describes these as tests the ITTF applies when deciding whether to approve a ball, so they are not something you can meaningfully check at home. When buying practice balls, the ITTF approval wording on the stamp and packaging is the practical signal. A star label on its own is not.
Common Questions
What is the official diameter of a table tennis ball?
40mm (Law 2.3). It replaced a 38mm ball in October 2000.
How much does an official table tennis ball weigh?
2.7 grams (Law 2.3).
What material are table tennis balls made of?
Plastic (Law 2.3). The Laws do not name a specific plastic. ITTF-sanctioned events moved from celluloid to plastic balls from 1 July 2014.
Why must the ball be matt instead of glossy?
The Laws require a matt ball but do not state why. Reduced glare is the usual practical reason.
What is the official bounce test for a table tennis ball?
In the ITTF approval test (Technical Leaflet T3), a ball must rebound 24 to 26cm when dropped from 30.5cm onto a standard steel block.
How does the star rating relate to the official specifications?
The ITTF leaflet only says that a numbered grade may not go above 3. It does not define what each number means, so the meaning of a star grade comes from the brand.
Did the 40mm diameter change actually affect gameplay?
Accounts of the October 2000 change say the larger ball’s greater air resistance slowed the game. These are secondary accounts, not ITTF measurements.
The Short Version
The Laws define the ball, the ITTF leaflet adds approval tests, and the two best-known changes are 38mm to 40mm in 2000 and celluloid to plastic in 2014.
- →Diameter: 40mm (38mm before October 2000).
- →Weight: 2.7 grams.
- →Material: plastic (the Laws name no specific plastic), replacing celluloid at ITTF-sanctioned events from 1 July 2014.
- →Color: white or orange, always matt finish, never glossy.
- →Bounce: 24 to 26cm from a 30.5cm drop onto a standard steel block, in the ITTF approval test.
- →Star grades are capped at 3 by the ITTF leaflet but not defined; look for the ITTF approval wording and 40+ on the stamp.
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