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What is the Official Size of an NBA Basketball? (Size, Weight, PSI, etc.)

The official size of an NBA basketball is size 7 (i.e. 29.5 inch circumference).

The current NBA game ball is made by Wilson, uses 100% genuine leather, and must be inflated between 7.5 to 8.5 PSI to be used in games.

Learn more interesting details about the official NBA basketball, including:

Let’s get started! 🏀

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Official NBA Basketball Size Details

Wilson Official NBA Basketball

The official game ball of the NBA is size 7.

Size 7 is the global standard for a men’s basketball.

For reference, a standard women’s basketball is size 6.

Youth (i.e. ages 9 and under) use a size 5 basketball.

Below are the circumference, diameter, weight, and PSI of an official NBA (size 7) basketball:

NBA Basketball Circumference

An NBA basketball has a circumference of 29.5 inches (approximately 74.9 cm).

The ball is measured around the channels, and by rule, can actually be between 29½ and 29¾ inches.

NBA Basketball Diameter

An NBA basketball has a diameter of approximately 9.39 inches (23.85 cm).

NBA Basketball Weight

According to Wilson, NBA or size 7 basketballs have a standard weight of 22 oz. (approximately 623.7 grams).

NBA Basketball PSI (Air Pressure)

According to the official rulebook, an NBA basketball must be inflated between 7.5 and 8.5 PSI to be used in games. Here is the actual quote (Rule No.1, Section II, point f):

(1) The ball shall be an officially approved NBA ball between 7 ½ and 8 ½ pounds pressure. (2) A minimum of nine balls must be made available to each team for pre-game warmup.

This specified air pressure gives the ball just the right amount of bounce preferred by NBA players. According to specification, when an NBA basketball is dropped straight down from a height of 72 inches, it should bounce back up 52 to 56 inches.

The consistency of bounce also has to do with the material and internal construction:

NBA Basketball Material & Construction

An NBA ball is made of four basic layers — bladder/core, winding layer, carcass, and cover.

100% Leather Cover

Dimpled leather basketball cover
Leather basketball cover being prepared (Photo from LA Times)

The official NBA basketball uses a 100% genuine leather cover. The leather is sourced from a Chicago-based company called Horween Leather (they also supply leather for NFL footballs).

This is different to most high school / college indoor basketballs which use a synthetic / composite leather cover.

A real leather cover feels more slick / rough at first, and requires time to break in. Once broken in, the ball will have a nice soft feel and better grip (especially when wet).

Wilson actually has a guide on how to break in its official NBA ball.

Internal Construction – Bladder, Winding, Carcass

Mockup of basketball internal construction
Four basic layers of a basketball: cover, carcass, winding, bladder

The bladder/core of the ball is made of a combination of butyl and natural rubber.

The core is then wrapped with a nylon/polyester thread which helps the ball maintain its spherical shape. This is called the “winding layer”.

Another layer of rubber (called the “carcass layer”) is then applied over the thread, and makes up the channels/seams of the ball.

The final leather cover is then applied.

Check out this interesting article for more details on how an NBA ball is made

Official NBA Basketball Brand (Wilson vs Spalding)

Spalding was the official NBA ball for 38 years.

Wilson has been the official game ball of the NBA since the 2021-2022 season.

Before that, Spalding was the official ball for 38 years (since 1983)!

Why did the NBA switch?

Well, the contract between the NBA and Spalding ended, and they “could not agree on terms” for a new deal (i.e. money 🤑).

The newer WIlson ball actually uses the exact same cover material as the old Spalding ball (sourced from Horween Leather Co), but has slightly changed the grip, channels/seams, and other details.

The size, of course, remains the same (i.e. size 7).

Learn more about Spalding vs Wilson basketballs here

NBA Basketball Size vs Other Leagues

How does the NBA ball size compare to other leagues around the world? Let’s take a look:

NBA vs FIBA basketball size

The official FIBA men’s basketball is the same size as the NBA ball (i.e. size 7 / 29.5” circumference).

FIBA uses millimeters and grams as official measurement units, so there is potential for the size to differ very slightly.

According to the FIBA equipment rules, a size 7 ball should be between 750mm – 770mm (29.5” – 30.3”) in circumference. Its weight should be between 580 – 620 grams (approx 20.46 – 21.87oz).

Molten brand is the official ball of FIBA (i.e. the Molten BG5000). The ball has very different design than the NBA ball. It uses 12 panels instead of 8, and the cover has natural leather texture instead of a pebbled texture.

NBA vs NCAA Basketball Sizes

Wilson EVO NXT is the official NCAA game ball

The official NCAA Men’s Basketball game ball is the same size as the NBA ball (size 7 / 29.5”)

It is also made by Wilson (i.e. the Wilson NCAA Evo NXT).

The main difference between the NCAA and NBA ball is that the NCAA uses a composite/synthetic leather cover instead of 100% genuine leather. The NCAA ball is also a brighter orange color.

NBA vs High School Basketball Size

The Wilson Evolution is a popular high school basketball

High school boys’ basketballs are the same size as the NBA game ball (size 7 / 29.5”).

The exact ball brand differs by school / area, and could be Wilson, Spalding, Nike, or other.

High school basketballs typically use a synthetic / composite leather cover instead of genuine leather (e.g. Wilson Evolution).

👉 Click here for a list of the best indoor basketballs

NBA vs WNBA / Women’s Basketball Size

The WNBA official game ball is smaller than the NBA ball.

It is size 6 (28.5” / 72.4 cm), with a standard weight of around 20 oz (approx. 567 grams).

Other women’s leagues like the FIBA Women’s, NCAA Women’s, or high school girls leagues also use a size 6 ball.

The WNBA ball is also made by Wilson, and uses a composite leather cover similar to the NCAA ball (not a genuine leather cover like the NBA).

NBA vs FIBA 3×3 Basketball Size

FIBA 3×3 ball is size 6, but has weight of a size 7 ball

The official FIBA 3×3 game ball is smaller in circumference, but weighs the same as the NBA ball. It is also made by Wilson.

It has a size 6 circumference (28.5”), but the weight of a size 7 ball (22 oz / 623 g).

The cover material is made with either rubber or synthetic leather (depending on competition), and uses Wilson’s patented “Wave Triple Threat Technology” pattern/texture.

Other Basketball Size FAQ

Here is a chart of common/standard basketball sizes:

Size CircumferenceWeightDescription (age / gender / etc.)
Size 729.5” (75cm)22 oz (0.62 kg)NBA; Official men’s size; Men’s ages 13+
Size 628.5” (72.5cm)18-20 oz (0.51 –
0.57 kg)
WNBA; Official women’s size; Girl age 12+; Boys age 11-13
Size 527.5” (69.9cm)14-16 oz (0.4 – 0.45 kg)Youth (Boys and Girls) aged 9-11
Size 425.5” (64.77cm)14 oz (0.4 kg)Children (Boys and Girls) age 8 and under
Size 3 / mini22.5” (55.9cm)10 oz(0.28 kg)Novelty-sized, “mini” basketball

Does NBA use size 7 basketball?

Yes, the NBA uses a size 7 basketball.

What is the official NBA basketball? How much does it cost?

The official NBA basketball is the Wilson NBA Official Game Basketball.

It costs approximately $200 USD.

Why does the WNBA use a smaller ball?

The WNBA and other women’s basketball leagues around the world use a smaller ball because women have smaller hands on average than men.

The WNBA ball is also lighter than the NBA ball (20 oz vs 22 oz).

Can 2 basketballs fit in a hoop?

The inside diameter of a standard NBA hoop (i.e. basket ring) is 18 inches (45.72 cm).

An official NBA size 7 basketball has an approximate diameter of 9.4 inches (23.85 cm).

Two NBA basketballs would have a diameter of 18.8 inches, which is wider than the hoop.

So, two NBA basketballs can NOT fit in a hoop at the exact same time.

One ball would need to go in slightly before the other to be able to fit.

Is 28.5 a men’s ball?

No, 28.5 is a women’s basketball.

29.5 is a men’s ball.

Is the Olympic basketball smaller?

No, the Olympic men’s basketball is the same as the FIBA men’s basketball (i.e. Molten BG5000). The FIBA ball is the same size as the NBA game ball (size 7 / 29.5”)


The official size of an NBA basketball is 29.5 inches in circumference (i.e. size 7).

This is the standard men’s size which is used in leagues around the world including FIBA, G League, NCAA, and high school.

If you’re interested in learning more about how the new Wilson NBA game ball is made, check out this interesting article by the LA Times.

What do you think of the NBA basketball size?

Should the WNBA start using the same basketball as men’s leagues?

Let me know in the comments below!

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Larry Lee

Larry Lee

Larry is a basketball addict, and the founder of Hoop Dojo. He started Hoop Dojo to share his love of the game and help the next generation reach their full potential.