The short and simple answer to How much does a baseball weigh? is between 5 to 5 1/4 ounces (141.74 to 148.83 grams).

Now for the long, slightly complicated, and downright strange answer:

There is no standardized exact weight – or even size – for a baseball!

According to the official MLB rules, and I quote:

a major league baseball weighs between 5 and 5 14 ounces (142 and 149 g), and is 9 to 9 14 inches (229–235 mm) in circumference (2 78–3 in or 73–76 mm in diameter)

That’s quite a lot of variance if you ask me!

However, the regulations don’t really apply so much to the weight and dimensions as they do to the manufacturing process. By controlling the manufacturing process, the MLB effectively controls the exact specifications of each ball, but they allow a little variance just to keep things a little simple!

Official Specifications for an MLB Baseball

The official specification for manufacturing a baseball is that it should be made out of two pieces of cowhide or horsehide, stitched tightly together using 108 double stitches(or 216 single stitches) – all done by hand! There have been some attempts to fully automate the manufacturing process, but they were unsuccessful.

Right now, MLB baseballs are made by Rawlings. The raw materials are shipped from the United States to Costa Rica, where they are assembled partially by machine, then stitched by hand, and shipped back to the United States for game use.

The very specific type of yarn and pattern used in stitching actually changes the aerodynamics of the ball, which is how pitchers can throw pitches like curveballs, sinkers, knuckleballs, cutters, and fastballs, to name a few.

History of the Baseball

Baseballs have undergone quite an evolution since the inception of the game in the mid 1800s. Over the course of 200 years, you’d expect that to happen, right?

The modern baseball has a center of rubber and cork, which is then wrapped with thick layers of cotton and yarn, which is then covered with rubber cement to hold it all in place. The final covering comes last, which is then stitched by hand.

Baseballs have gone through a number of evolutions:

  • The dead-ball era
  • The live-ball era
  • World War II
  • After World War II – today

1. Dead Ball Era

In the early dead ball era, baseballs were made by hand by pitchers, so quite literally no two baseballs were alike. Upon the founding of the National League, a pitcher named A.G. Spalding pitched(heh) a design to the league which contained a rubber core. The league adopted this design, giving Mr Spaldings business a strong footing.

However, this ball was heavily favorable to pitchers, and a quick glance at early baseball statistics will show you that it was a very pitcher-friendly game, with very low home run averages and low total home runs.

2. Live Ball Era

Starting in the 1920s, Mr Spalding decided to start using Australian wool to make the yarn used in wrapping the baseball cores. The new yarn suddenly threw the balance out of the favor of pitchers and into the favor of batters.

The seasons following the first introduction of the Australian yarn ball saw huge upticks in hits, home runs, and a general trend towards a more offensive game.

To further upset the pitchers, spitballing(it’s what it sounds like) was outlawed, and balls began to be replaced in games once they got soft and dirty, further favoring batters.

During this era, legendary players like Lou Gehrig were literally smashing it all over the place.

In 1934, the American League and National League agreed on a standardized manufacturing process for a ball. A process, which if you ask me, is highly precise and complicated!

A New York Times Article “How much does a baseball weigh?” quotes:

The ball will have a cushion cork centre weighing 7/8 of an ounce, the cushion being provided by one layer of black rubber and another of red, the reason for which was not made known.

Then come 71 yards of blue gray woolen yarn, building the ball to a circumference of 7 3/4 inches and the weight to 3 1/8 ounces. Next, 41 yards of white woolen yarn is wrapped on, and the circumference has become 8 1/4 inches, the weight 3 7/8 ounces. A coat of special rubber cement is applied.

Two more wrappings of yarn, the first 41 yards of blue-gray woolen, the second of a final 100 yards of 20/2 ply fine cotton, provide a circumference of 8 7/8 inches and a weight of 4 3/8 ounces, to which another coat of rubber cement is applied.

The cover is a special tanned horsehide, weighing 1/3 ounce and 5/100 of an inch thick, and sewn with a double stitch of four-strand red thread. The finished ball is 9 to 9 1/8 inches in circumference and should weigh 5 to 5 1/8 ounces.


3. World War II “How much does a baseball weigh?”

World War II came along, and America’s primary sources of rubber imports were cut off. Since rubber was a necessary raw material in arms and ammunition, it became restricted from use in all non-essential manufacturing, which included baseballs.

The wartime baseball had a strange cork center, and no rubber coating on the core – instead, there was a rubber-like substance which barely did the trick.

The scales tipped back in favor of the pitchers, and the initial war years saw a huge slump in batting. However, by 1944, rubber was synthesized successfully and since we no longer needed to import it, there was plenty of it again and baseballs returned to how they were, pushing the scale back towards batters.

4. Post World War II – Modern day

Not much has really changed about the baseball since then. A 1958 report quote reads strikingly similar(with minor differences) to the earlier one quoted above:

Major league baseballs start with a core of cork mixed with a small amount of rubber. This is covered by a layer of black rubber, then by a layer of red rubber. It is then ready for the winding process, where yarn is added to the core. This is done on a revolving machine…in a humidity- and temperature-controlled room.

Yarn windings consist first of 121 yards of rough gray wool, forty-five yards of white wool then 53 yards of fine gray wool and finally 150 yards of fine white cotton. After these layers have been added to the sphere, it is coated with rubber cement. Then two pieces of horsehide in the shape of the figure ‘8’ are hand-stitched with red thread to cover the ball.

….Each ball has 108 hand-stitched double stitches in its cover. A finished ball weighs from 5 to 5 1/4 ounces and measures not less than 9, nor more than 9 1/4 inches.

This fascinating video from the discovery channel shows how baseballs are made:

Bullpen Aces