Los Altos & Los Altos Hills Little League (Bay Area): Bat Rules & Guidelines

Baseball Bat Rules and Selection Guidelines

History of the Baseball Bat

Major League Baseball requires bats to be made of one piece of solid wood, with a maximum barrel diameter of 2.61 inches, and a maximum length of 42 inches.  Early in his career, Babe Ruth used a 36-inch, 54-ounce bat.  But decades of research and experimentation have shown that bat speed is of primary importance for success in hitting, and hence there has been a trend toward shorter and lighter bats.  Ruth experimented with shorter and lighter bats during his career, obtaining better results. Most MLB players today use 33 or 34 inch bats, typically weighing 30 or 31 ounces. At 6'5" and 250 pounds, 2016 MLB Home Run Derby champion Giancarlo Stanton uses a 34-inch 32-ounce bat.

The 1970's saw the introduction of aluminum bats for youth baseball.  The metal bats were manufactured to be lighter and stiffer than wood bats of similar size.  While the "drop" (the difference between length in inches and weight in ounces) of a MLB wood bat is typically 3 (for example, 34 inches and 31 ounces), a typical aluminum T-Ball bat for a 5 year-old player today has a drop of 12 (for example, 25 inches and 13 ounces).  The lighter aluminum bats are easier to swing for younger players - more hits, more fun.

During the 1990's bat manufacturers began incorporating reinforced carbon fiber polymer into bats.  Bats made entirely of this composite material have been referred to as "composite" bats, while bats with a composite handle and an aluminum barrel have been referred to as "hybrids."  The composite material can provide advantages over all-aluminum bats in terms of better weight distribution, a larger "sweet spot," better vibration damping (to reduce hand sting), and increased trampoline effect (composite bats with high trampoline effect can hit balls harder and with higher velocity than wood or aluminum bats).  The high trampoline effect of early composite bats was widely regarded as a potential safety hazard, and also frowned upon as an aesthetic departure from the integrity and spirit of the game.  As a result, the last 10 years have seen several testing and certification standards emerge to limit trampoline effect in composite bats.

Since 2011, colleges and high schools have required non-wood bats to follow the BBCOR (Batted Ball Coefficient of Restitution) standard.  All BBCOR bats have 2 5/8 (2.625) inch barrels with a drop of 3.  To be legal for college and high school, non-wood bats must have a "BBCOR Certified .50" stamp.  The BBCOR standard regulates how much energy is lost during the bat's contact with the baseball - the higher a bat's tested value, the more trampoline effect it has. The .50 value - just slightly higher than that of wood bats - is the maximum allowed.


For younger elementary and middle school players, various youth baseball organizations have developed their own bat rules, sometimes following other testing and certification standards.


Little League Bat Rules

For the past several years, and for 2017, the Little League International's bat rules have been as follows:
For ages 12 and under (Majors, Minors, and T-Ball divisions):
Bats shall be no longer than 33 inches with barrels no more than 2 1/4 (2.25) inches in diameter.  Non-wood (aluminum and composite) bats shall be certified as conforming to the BPF (Bat Performance Factor) standard and carry a "USSSA BPF 1.15" certification stamp.  (For Girls Softball, BPF 1.20 or BPF 1.15 are allowed.)  In addition, composite-barrel bats must be specifically listed on Little League International's 
list of approved composite bats.
For ages 13 and 14 (Juniors division):
Bats shall be no longer than 34 inches with barrels no more than 2 5/8 (2.625) inches in diameter.  Aluminum-barrel bats should carry the "USSSA BPF 1.15" stamp, but composite-barrel bats must follow the BBCOR standard (2 5/8 barrel, drop of 3) and must carry the "BBCOR Certified .50" stamp.

Note that if your player participates in a club or travel baseball program in addition to Little League, most local tournament organizations allow "big barrel" 2 3/4 (2.75) diameter bats as long as they are marked with the "USSSA BPF 1.15" stamp. However, these "big barrel" bats are not allowed in Little League.


Starting January 1, 2018, Little League is expected to adopt a new bat standard from USA Baseball.  If you are purchasing a new bat in 2016 or 2017, please keep in mind that the bat may no longer be legal for use in any Little League game or practice in 2018.  For 2018, all bats for Juniors, Majors, Minors, and T-Ball must have a USA Baseball Stamp and a maximum barrel diameter of 2 5/8.  BBCOR bats will no longer be allowed for Juniors.  Bats certified to the new standard are expected to go on sale starting in September 2017. More information will be distributed as it becomes available.


 Los Altos & Los Altos Hills Little League Bat Length and Weight Recommendations

Our league provides a shared bat for T-Ball teams, but after T-Ball players are expected to have their own bats, or ask to borrow a bat from the coach or a friend on the team.  You don't need to buy a new bat every year, and while expensive composite bats can provide a slight advantage for more experienced players, most young players will do fine with a $30 aluminum bat.  We recommend a 25-inch 12 ounce (drop 13) bat for 5 year-old players, adding about an inch in length for each year of age, and gradually reducing the drop (thereby increasing the weight) as players get older. The guidelines below are approximate - use your judgement if your player is larger or smaller for his/her age.

Age 5:   25 inch, drop 13
Age 6:  26 inch, drop 12
Age 7:  27 inch, drop 12
Age 8:  28 inch, drop 12
Age 9:  29 inch, drop 11
Age 10:  30 inch, drop 11
Age 11:  31 inch, drop 11
Age 12:  32 inch, drop 10
Age 13:  32 inch, drop 8
Age 14:  33 inch, drop 5 (or drop 3 to get ready for high school)