How much must a table tennis ball weigh under international rules?

A table tennis ball must weigh 2.7 grams under international competition rules.

The ball is also standardized at 40 millimetres in diameter and must be spherical. Since 2014, approved competition balls have generally been made from plastic rather than celluloid, although the required weight remained 2.7 grams. Balls are commonly white or orange, with the choice depending on playing conditions and visibility.

The weight is measured for the ball itself, not its packaging or a printed identification mark. Small differences in weight, roundness, hardness, and seam quality can affect bounce and flight, so tournament balls are manufactured and tested to meet the relevant specifications.

The modern 40-millimetre ball replaced the smaller 38-millimetre standard in 2000. That change slightly slowed play and increased the ball’s visibility, while the later material change addressed safety and manufacturing concerns associated with celluloid.