Ping pong balls: stars, plastic and 40+ explained
The official table tennis ball is 40 mm across, weighs 2.7 g and is white or orange with a matte finish. Since 2014 competitions use plastic balls, marked 40+. Stars are a manufacturer quality grade: 3 stars for match play and competition, 1 or 2 stars for practice and fun.
In this article
Ping pong balls all look the same, but they are not. Size, material and quality change the bounce, the spin and how long a ball lasts. Knowing how to read the stars and markings on the box saves you from balls that crack in a week or bounce off line.
Official ping pong ball size and weight
Under ITTF rules, the official ball is:
| Feature | Rule |
|---|---|
| Diameter | 40 mm (about 1.57 in) |
| Weight | 2.7 g (under a tenth of an ounce) |
| Color | White or orange |
| Finish | Matte |
| Material | Celluloid or similar plastic (today, plastic) |
Until 2000, the official ball was 38 mm. The switch to 40 mm made the ball slightly slower with a bit less spin, which helped lengthen rallies.
Celluloid vs plastic: what "40+" means
For decades, balls were made of celluloid, a flammable material that was hard to ship and produce. In 2014 the ITTF moved competitions to plastic balls. To tell them apart, they are marked 40+.
| Celluloid | Plastic (40+) | |
|---|---|---|
| Era | Standard until 2014 | Official standard since 2014 |
| Spin | A little more | A little less |
| Bounce | Lower | Slightly higher |
| Where to find it today | Rare | Everywhere |
Plastic balls come seamed (two halves joined) and seamless (made in one piece). Seamless balls tend to be rounder, while seamed balls are more common. Both can be ITTF-approved.
What the stars mean
Stars are not part of the rules. They are a quality grade from the manufacturer.
| Stars | Typical use | What to expect |
|---|---|---|
| 3 stars | Competition and serious practice | Rounder, even weight, consistent bounce |
| 2 stars | Practice | Good quality, small variations |
| 1 star or none | Casual play, multiball, robots | More variation in weight and roundness |
For sanctioned tournaments, what matters is that the ball is ITTF-approved, with the marking printed on it. These are almost always 3-star balls.
Training balls in bulk
For multiball training and table tennis robots, players buy training balls in large boxes. They do not need to be 3-star, but they should match the size and material you play matches with, so the bounce feels similar.
Which ping pong balls to buy
- Basement and backyard play: 1 or 2 star 40+ plastic balls.
- Club practice: 2 or 3 stars, the same type used in your local tournaments.
- Competition: ITTF-approved 3-star balls, the same ball as the event.
- Multiball and robots: bulk training balls, all the same kind.
A simple tip: do not mix brands and materials in one session. Different balls bounce differently and hurt your consistency.
How to test a ball
- Spin test: spin the ball on the table like a top. If it wobbles a lot, it may be off-center.
- Bounce test: drop several balls from the same height onto the table. Good ones bounce almost identically.
- Sound: a dull sound on the bounce can mean a crack.
- Gentle squeeze: if one spot gives more than another, the wall is uneven.
How long a ball lasts
It depends on the material and how hard you hit. Pull cracked balls out of play right away: they bounce wrong and can teach you the wrong timing. Store balls somewhere dry and away from heat, which can warp them.
Frequently asked questions
What size is a ping pong ball?
40 mm (about 1.57 inches) across, weighing 2.7 g. It is white or orange with a matte finish.
What does 3-star mean on ping pong balls?
It is the manufacturer's highest quality grade. The ball is rounder and more uniform, used in competition and serious practice.
What does 40+ mean on a ping pong ball?
It marks the plastic ball that replaced celluloid in official competition from 2014.
Are ping pong balls and table tennis balls the same?
Yes, same kind of ball. The difference is quality: cheap recreational balls vary more in weight and roundness.
Are orange ping pong balls legal?
Yes. The rules allow white or orange. You pick the one that contrasts best with the background and clothing.