What Is a Baseball Bat Drop?
As you shop for the perfect baseball or softball bat online, you’ve likely come across the term “drop” or a negative number (-8, -10, etc.) printed on your bat’s barrel. But, what does bat drop mean?
Bat drop and the negative number that denotes it represents and is calculated as your bat’s length to weight ratio. To calculate bat drop, take the difference between the weight of your baseball bat (in ounces) and its length (in inches)
The bat drop of a youth baseball bat that is 30″ long and weighs 20 oz is calculated as weight minus length, i.e.:
20 oz (bat weight) – 30” (bat length) = -10 or drop 10 (bat weight)
Why is this important? Well, lower “drop” numbers represent a heavier bat, while higher numbers represent lighter bats, e.g., when comparing a drop 8 vs a drop 10 bat, a drop 8 bat is heavier than a drop 10 bat. Similarly, a drop 10 bat is slightly heavier than a drop 11 bat.
Is Bat Drop Important?
Bat drop is important to some degree, meaning that you can’t purchase a bat without worrying about its drop weight. High school and collegiate leagues, for instance, require that all players use drop 3 or -3 bats.
Most guides you find online will give a basic bat size chart about how the player’s age, height, and weight, matched to a bat’s drop, weight, and length, are the markers you need to choose the right bat.
While this isn’t entirely untrue, it only scratches the surface of what you need to consider when choosing the right bat for you. Bat drop isn’t the only yardstick you should consider. Differences in printed vs. actual weight, bat weight distribution, and differences in materials, styles, and shapes all add to the equation.
Printed vs. Actual Bat Weights
Printed vs. Actual bat weights often vary by as much as 0.5 oz less to 3.0 ounces more, with most bats recording a 1.5 oz addition on average. These inaccuracies are misleading and have a significant impact on player performance and confidence when they frequently miss the ball or get weak contact when they do hit it.
Sadly this practice has become the norm in recent years due to:
- Manufacturing variance, which accounts for up to 0.25 oz.
- Some manufacturers print weights without accounting for bat grip tape, which can add 0.5 to 1.0 oz.
Unfortunately, coaches and parents will have to work around this by weighing bats themselves to ensure they get the right weighted bat.
If the bat is shrink-wrapped, subtract 0.3 oz, which is the approximate weight of the bat’s shrink wrap. Bats that go over the printed weight by 2 or 3 oz more need to be exchanged for something lighter.
Bat Weight Distribution
Heavier bats hit farther, but they’re harder to swing. Conversely, lighter bats make it easier to hit the ball. This difference is all down to MOI, a term used to describe how difficult a bat is to swing.
MOI, or moment-of-inertia, measures how difficult it is to change the rotational velocity of an object rotating around the pivot point. The larger the MOI, the more difficult it is to change the rotational speed of the object. MOI depends on the object’s total mass and how it distributes about the pivot point.
Bat manufacturers can focus more load towards the handle, resulting in a lower MOI bat called a balanced bat. Manufacturers can also focus weight towards the end of the barrel resulting in an end-loaded bat. Read about the differences between balanced vs. end-loaded bats.
Take two identical bats of 30″ length and 20 oz (drop 10 or -10) that vary in weight distribution, i.e., one is end-loaded, while the other is balanced. An 11-year-old, 4′ 8″ player will be okay swinging the balanced bat but may have a tough time getting solid contact with the end-loaded bat. The end-loaded bat has a higher MOI, or swing weight, despite sharing length and width numbers with the balanced bat.
Additionally, two bats of 32″ and 31″ that weigh the same and have weight distributed equally will have different MOI numbers. The MOI of the 32″ bat is higher than the 31″ bat because the weight is further from the handle on the longer bat.
Sadly, MOI doesn’t appear on bats. Some manufacturers, however, will print swing weights instead of actual weights, which is somewhat better. Printing MOI numbers on bats would help players understand that bigger MOI numbers represent a bat that’s harder to swing and thus needs a bigger/stronger player.
In the interim, the best way to determine the correct weight is to weigh the bat.
Bat Materials, Shapes, and Styles
The two basic materials you’ll find when shopping for a bat are aluminum (aka alloy) and composite. These two materials swing differently. Aluminum, which is stiffer, is easier to swing/control. Composite flex more than aluminum bats, making them slightly more challenging to control.
Style of Bat
The style of bat adds more complexity to the mix. For instance, the ax-like knobs on Axe bats push the hands 1/4″ up the handle, which lowers the MOI and swing weight.
Another style difference is one-piece versus two-piece construction. One-piece bats are easier to swing because two-piece bats flex at the connection piece that joins the handle and the barrel.
The Shape of the Bat
Barrel widths (2 5/8″ for USA bats and BBCOR, and 2 3/4″ for seniors) dictate how easy it is to make contact, especially for beginners. So the shape of the bat further influences how easy a bat is to swing, an additional consideration in addition to the bat’s drop weight.
Baseball bat drop gives a fundamental understanding of what you need to consider when choosing a bat. However, given all the factors mentioned above, drop weight is not an absolute metric that you can use.
And while the best solution would be to mandate lab testing and MOI figures feature on every youth bat, this isn’t likely to happen soon. Before then, weigh every new bat so that you know up-front if the bat is too heavy. Also, do some soft toss drills into a net and watch out for how difficult or easy it is for your player to make contact