Baseball Size & Weight

An official baseball is about 73 mm (2.9 in) in diameter, 22.9 to 23.5 cm around, and weighs 142 to 149 grams. Major League Baseball has held those numbers for more than a century, and the rulebook still specifies them as circumference and weight.

This guide covers the exact baseball dimensions, how it compares to a softball and a tennis ball, why the ball is quoted by circumference, and how it sizes up against an adult fist.

Quick Answer: How Big Is a Baseball?

A baseball has a circumference of 9 to 9.25 in (22.9 to 23.5 cm), which is a diameter of about 73 to 75 mm (2.87 to 2.94 in). It weighs 5 to 5.25 oz (142 to 149 g).

Baseball Dimensions at a Glance

• Diameter: ~73 mm / 7.3 cm / 2.87 in
• Circumference: 229 – 235 mm / 22.9 – 23.5 cm / 9 – 9.25 in
• Weight: 142 – 149 g (MLB Rule 3.01)
• Construction: cork-and-rubber “pill”, wound yarn, cowhide cover with 108 double stitches
• Standard: Official Baseball Rules, unchanged in essentials since 1872

What Does a Baseball Look Like in Size?

A baseball sits in the palm and is roughly the size of a closed adult fist, or a large apple. Its 73 mm diameter is a little wider than a tennis ball and about the same as a cricket ball. Two baseballs side by side span about 146 mm, close to the length of a standard smartphone.

6 Everyday Comparisons for a Baseball

1. A tennis ball (67 mm, 58 g) is about 6 mm smaller across and roughly a third of the weight.
2. A softball (30.5 cm circumference, ~97 mm diameter, 178 g) is about 24 mm larger across and heavier.
3. A cricket ball (about 72 mm, 156 – 163 g) is nearly the same size but slightly heavier.
4. An adult fist (about 70 – 90 mm across the knuckles) is close, which is why “size of a fist” is the usual shorthand.
5. A medium apple (about 75 mm) is a close visual match.
6. A billiard ball (57.15 mm) is about 16 mm smaller and heavier at 170 g.

Baseball Size in Different Units

Why a Baseball Is Quoted by Circumference

Like most sports balls, the baseball rulebook specifies the distance around the ball, not across it, because a tape around the equator is the practical way to check a ball on the bench. The 9 to 9.25 in circumference converts to a diameter of about 2.87 to 2.94 in. Manufacturers build to the circumference and weight; the diameter is a derived figure.

Common Mistakes When Comparing Baseball Dimensions

1. Quoting circumference as the “size.” A baseball is 9 in around but only about 2.9 in across.
2. Confusing a baseball and a softball. A softball is much larger (about 30.5 cm around) despite the name.
3. Assuming the ball never changed. The core materials and manufacturing have shifted over the decades even though the size and weight targets held.
4. Ignoring the weight range. A quarter-ounce spread (7 g) is allowed, enough to feel in the hand.
5. Treating a youth ball as regulation. Youth leagues sometimes use a slightly lighter or reduced-impact ball.

Frequently Asked Questions

What is the diameter of a baseball?

About 73 to 75 mm (2.87 to 2.94 in).

What is the circumference of a baseball?

9 to 9.25 inches (22.9 to 23.5 cm).

How much does a baseball weigh?

5 to 5.25 ounces (142 to 149 g).

Is a baseball bigger than a tennis ball?

Yes, by about 6 mm across, and it is roughly three times heavier.

Is a baseball the same as a softball?

No. A softball is much larger, about 30.5 cm around.

How many stitches are on a baseball?

108 double stitches, or 216 individual stitches.

Final Takeaway

An official baseball is about 73 mm (2.9 in) across, 22.9 to 23.5 cm (9 to 9.25 in) around, and 142 to 149 grams. It is a little bigger and much heavier than a tennis ball, far smaller than a softball, and about the size of an adult fist or a medium apple.