In this article, you will learn the exact size and weight of a regulation baseball.
The game of baseball has been around since the early 1800’s and is considered to be the second most popular sport in the USA after American football.
Baseball is sometimes confused with softball which is another popular sport played around the world.
The ball used in softball is larger and heavier than the ball used in baseball.
Most people are familiar with what a baseball looks like but are unaware of it’s actual size and weight.
Let’s have a look at the size and weight of a baseball in more detail.
How big is a baseball?
A baseball used in professional leagues like Major League Baseball (MLB), has diameter between 2.86 – 2.94 inches and a circumference between 9 – 9.25 inches. A baseball weighs between 5 – 5.25 ounces.
Baseballs used in little league and other non professional leagues will use baseballs that are slightly smaller and lighter than baseballs used in pro leagues.

Baseball vs Softball size and weight: What is the difference?
The game of softball is very similar to the game of baseball but there are some differences. One of the most noticeable differences is the size of ball being used.
As mentioned, a softball is larger and heavier than a baseball.
A softball can either be 11 or 12 inches in circumference depending on which game is being played.
An 11-inch ball is used during a fast pitch softball game and a 12-inch ball is used for a slow pitch softball game.
The 12-inch ball is slightly softer than the 11-inch ball.
A softball has diameter between 3.5 – 3.8 inches compared to a baseball which has diameter of 2.86 – 2.94 inches.
Depending on the size of the ball, the weight will vary.
An 11-inch softball weighs between 5.785 ounces and 6.125 ounces.
A 12-inch softball weighs between 6.125 ounces and 7 ounces.
A softball can weigh up to 2 ounces heavier than a baseball.

What is a baseball made of?
A baseball is made by taking a cork center which is wrapped in yarn then covered in natural cowhide or synthetic leather. There are 108 stitches of red dyed thread on each baseball.

The process of making a baseball is quite detailed and very interesting.
The following video explains how a professional league baseball is made from start to finish.
Factors that affect the size and weight of a baseball
When a baseball is made, careful planning goes into ensuring all baseballs are the same size and weight. Of course, if the rubber core or cork being used is slightly larger or smaller, this can affect the overall size of the ball.
Also, if the leather being used is slightly thinner or thicker, this can affect the overall size and weight of the finished baseball.
Outside air temperature can affect the size and weight of a baseball.
On warm days, the air inside the baseball tends to expand which can increase the overall size of the baseball.
Just the opposite happens on cooler days where the air inside the ball tends to contract resulting in the ball shrinking slightly.
Although the affect of temperature on a baseball’s size and weight are slight, it still occurs.
Another factor that can affect the size and weight of a baseball is from it being used over time.
The more a baseball is hit with a baseball bat, tossed between players, and abused over time, it can become damaged and change shape.
The leather can tear and the cork or rubber core can shrink and compress causing the ball to become smaller.
