How Much Does a Baseball Weigh?
Official Specs & Full Breakdown

Whether you are here for a physics problem, a trivia question, or just curious what that ball in your glove actually weighs — here is everything you need to know about official baseball weight, how it breaks down by level of play, and why it matters.

Official MLB Baseball Weight

According to Rule 3.01 of the Official Baseball Rules, a major league baseball must weigh between 5 and 5.25 ounces (141.7 to 148.8 grams) and measure between 9 and 9.25 inches in circumference. These specifications have been in place for over a century and are enforced by the umpire crew chief before every game.

Each MLB team receives about 100 baseballs per game, and Rawlings — the official manufacturer — produces roughly 2.4 million balls per year to meet demand. Every ball is inspected to ensure it falls within the official weight and circumference tolerances before it ever reaches a pitcher's hand.

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Baseball size — circumference, diameter, and weight

Weight is only one of the official specifications. Here is the complete size profile of an official MLB baseball.

Baseball weight by level of play

The official weight is consistent from high school through the pros, but younger Little League divisions use a slightly lighter standard. Here is the full breakdown.

The takeaway: once you are at the Majors level in Little League (typically ages 9–12) you are using the same ball specification as MLB. The weight difference only exists for younger age groups where reducing the ball weight helps developing players pitch and field more safely.

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How a baseball is made — why weight matters

A baseball is a precisely engineered object built in layers. Understanding the construction helps explain why the weight spec is so carefully maintained.

At the center is a cork and rubber core called the "pill," which weighs about half an ounce on its own. Around that, three layers of wool yarn are tightly wound — a layer of blue-gray wool, then white wool, then a final layer of white cotton yarn — adding most of the ball's mass. The entire assembly is then wrapped in two layers of cowhide leather, stitched together by hand with 108 red cotton stitches.

The weight of the finished ball is a direct result of how tightly the yarn is wound and the density of the leather. Even small variations in winding tension or leather thickness can affect the ball's performance characteristics, which is why Rawlings maintains strict tolerances and inspects every ball before shipment.

A closer look at official baseball specifications and manufacturing.

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Baseball weight vs other sports balls

A baseball is heavier than a tennis ball or golf ball but significantly lighter than a football or basketball. It is essentially designed to be the heaviest object a pitcher can throw at maximum velocity without causing arm injury — a balance refined over more than 150 years of play.

Does baseball weight affect performance?

Within the legal tolerance of 5 to 5.25 oz, weight differences are imperceptible to most hitters. A 0.25 oz variation is less than 5% of the ball's total weight and falls well within the natural variation any pitcher already accounts for in their grip and release.

Where weight matters more is in the manufacturing process. A ball that is too light tends to be wound too loosely, which reduces the density of the core and can create unpredictable seam behavior off the bat. A ball that is too heavy is usually over-wound, which creates a harder, less responsive surface. Both extremes are caught in Rawlings' inspection process before the ball ever reaches a game.

For youth players, using the correct weight ball for your age group matters significantly more. A 4 to 5 oz ball is meaningfully lighter than a regulation 5.25 oz ball and is specifically designed to reduce arm strain on developing pitchers. If your Little League program is using regulation weight balls with 7-year-olds that is worth flagging to the coaches.

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Frequently asked questions