A Detailed Guide to What Baseball Bats Are Made of


Seven aluminum baseball bats.

When you’re talking about baseball equipment, there are two pieces that go down to the very foundation of what the game is: the bat and the ball.

Obviously, to hit said ball, you need a bat, and consequently, as the game has evolved, so have the bats that are in charge of putting the ball in play.

So, what are baseball bats made of?

In all levels of professional baseball, only bats made out of one solid piece of wood are allowed, while in most forms of amateur baseball, aluminum bats are allowed, though some amateur leagues only allow wood bats. There are restrictions on bat specifications at various levels as well.

As important as having the right bat for the job is to the hitter, several restrictions and specifications exist, all as part of maintaining the balance between hitters and pitchers. So let’s dive into what those are.

What Are the Dimensions of a Professional Baseball Bat?

The rules of baseball allow a bat to vary in size and weight, though there are some parameters in terms of how long and thick a bat can be.

Major League Baseball (MLB) rules state that the bat must be a smooth, round stick made of one continuous piece of wood, which cannot be more than 2 5/8” in diameter at any point, or be more than 42” long. Additionally, up to 1 ¼” of the end of the bat may be hollowed out, or “cupped.”

Because a thicker bat would in theory aid a hitter in hitting more pitches, virtually all bats reach the maximum thickness.

In terms of length, no one is known to have used a stick close to the 42” maximum, while several have been known to use 36” bats, and 1960’s slugger Frank Howard was known to have used a 37” bat.

On the other end, Hall of Famer Tony Gwynn regularly used bats measuring just 32 ¼” long, in comparison to the normal size, which for most major leaguers falls in the 33-34” range.

In 2013, the most popular size in MLB was said to be 34”, 32oz, though it’s unclear if that remains the case several years later.

When it comes to weight, there are no restrictions, so MLB bats have been known to see a wide variety in weight. Babe Ruth is known to have used bats weighing up to 54oz when bats over 40oz were common before World War II.

However, since then, lighter bats have been more common, with the aforementioned 32oz being a popular weight, with 33oz bats being common as well.

The lightest known bats in MLB belonged to Ozzie Smith and Rod Carew, a pair of Hall of Famers who used 29oz bats.

How Big Are Amateur Baseball Bats?

Wooden shed full of baseball bats and helmets.

All the bats that we covered in the last segment belonged to the best of the best: major leaguers.

Naturally, for the vast majority of baseball players, they don’t need the custom-made 34”, 33oz Louisville Sluggers the big leaguers use.

In amateur baseball, bats typically range from 24-34” depending on age level and are almost exclusively several ounces lighter than their length (referred to as a “drop”). Virtually all amateur players use aluminum bats as well, which are subject to their own rules and regulations.

As for the rules and regulations for aluminum bats, we’ll cover that later on. For now, we’ll stick with length and weight on these bats.

In high school baseball, all-aluminum bats must not be more than three ounces lighter than their length (said as “drop three,” or written as “-3”). Sound confusing?

Well, it’s actually rather simple. What this means is that a 32” bat may not weigh less than 29oz, a 33” bat cannot be less than 30oz, and so on.

Below high school play, bats are usually shorter, but also have much larger drops, due to many kids lacking the muscle mass at a young age to swing a heavier bat.

For example, Louisville Slugger suggests that ages 10 and under use a -10, a -8 bat for ages 11-12, and -5 for 13-year olds, with high school rules going into effect at older ages.

Additionally, Louisville Slugger provides a chart to use as a general guide for choosing the right length of bat for youth baseball players.

The chart uses the heights and weights of players as a guide for determining how long of a bat the player would likely need, then using their age to determine the recommended drop in weight.

As a result, you’ll find bats that are very small at the lowest levels of youth baseball, but also those rivaling professional models in size at the high school level.

With all the options out there, though, it’s easy to find one that’s right for any player.

Restrictions for Youth Baseball Bats

Because of the nature of aluminum bats, manufacturers can easily alter their composition to make balls fly off the bat at greater speeds than wooden bats.

However, due to competitive and safety issues, various restrictions are in place to ensure that metal bats are safe to use.

In 2011, the NCAA declared that all bats used in intercollegiate play must be certified to have passed Bat-Ball Coefficient of Restitution (BBCOR) standards, with the NFHS declaring the same thing for high school play in 2012. Most other youth organizations have adopted similar rules.

What BBCOR means is measuring the so-called “trampoline effect” of the ball off the bat.

What this means is that pre-BBCOR bats had some “give” to them, so that they flexed ever-so-slightly, with the ball maintaining more energy than if hit by a wooden bat, therefore going further off the bat—and coming off faster, which was becoming dangerous for youth baseball.

Because wood bats don’t have as much give as pre-BBCOR bats, balls don’t fly as fast or as far off of them, so the idea was to make aluminum bats that behaved similarly to wood bats.

The result were bats that were much less potent than previous models, resulting in some of the lowest offensive numbers in decades in college.

USA Baseball, the national governing body for baseball in the US, introduced their own standards that were somewhat similar to BBCOR and aimed to accomplish the same goal of making metal bats behave more like wood bats.

USA Baseball-approved bats have thumb-sized stickers on the barrel reading either 1.05, 1.10, or 1.15, while BBCOR stamps read “BBCOR .50.”

Different Types of Baseball Bats

A black and brown fungo bat lying in the grass.

For the most part, bats can be categorized simply by either wood or aluminum.

However, there are several different types of wood bats, as well as notable differences between true aluminum bats and what we call aluminum bats, which these days are mostly composite bats.

Wooden bats typically are made out of white ash, birch, or maple, with bamboo being a newer option, as well as wood composite bats featuring two different kinds of wood. In addition to traditional aluminum bats, which are prone to denting, composite bats are much more durable and powerful.

For wood bats, the important factors are whether the wood is solid enough to withstand the force of hitting a baseball and whether it’s light enough to effectively swing and generate power.

This narrows the dozens and dozens of types of wood out there down to four viable options: ash, birch, maple, and bamboo. In the early 20th century, hickory was a popular choice but fell out of favor for being too heavy.

Maple Baseball Bats

Known for being a very hard wood, leading to balls jumping off the surface more, but is also prone to breaking quicker.

Ash Baseball Bats

Known for being more flexible than maple, but repeated use will cause a separation of grain that makes balls not fly as far.

Birch Baseball Bats

Tends to be the best of both worlds: tougher than ash and more flexible than maple.

Bamboo Baseball Bats

Bamboo is different in that the trees are hollow, so they must be pressed into strips. These strips then need to be pressed together to form the shape of a bat.

This results in bats that are very durable, but also are not one continuous piece and that’s why they aren’t allowed in MLB and are only allowed at youth levels with a BBCOR sticker.


There is also a composite wood option, which is another relatively new option. These bats are made of wood that’s either shaved or cut into strips, that are then glued together.

Sometimes they are reinforced with plastic as well. These bats are marketed as being extremely durable but are not allowed in the professional ranks, as well as some amateur organizations.

On the non-wood side, those bats are often all referred to as aluminum bats, though as we said earlier, that is a bit of a misnomer. Traditional aluminum bats were first introduced in the 1920s but did not become viable for game use until the 1970s, with the NCAA legalizing them in 1974.

Over time, the composition of metal bats changed from primarily aluminum to carbon fiber and Kevlar, among other materials, to create a bat that got stronger with repeated use.

As a result, these bats, which in the factory passed performance standards set by the NCAA in 1999, actually far exceeded them on the field, leading to the new BBCOR restrictions in 2011.

With the way bats are made these days, it’s impossible to discernably say which bats feature what materials since different manufacturers have different formulas to produce a bat that is safe, durable, doesn’t wear out quickly, and is economical.

That said, whether you want to just play little league, or play beyond high school, whether that’s in college, the pros, or just in an adult league, there is certainly a bat out there that’s perfect for your game.

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Steven G.

My name is Steven and I love everything sports! I created this website to share my passion with all of you. Enjoy!

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