Here you can find baseball bat rules for many of the well-known leagues of youth and amateur baseball. Learn about the rules concerning bat weight and length.
Click on the link to which ever league you or your child plays in to open a new window and look at that league’s website. On the league websites you should see a link that says "Rules" or "Regulations." You should be able to find what you need there.
The main thing you are looking for is to see if there is a limitation on the length or the weight of the bat. Most leagues have a limit on the "drop." The drop is the difference between the length of the bat in inches, and the weight of the bat in ounces. High school and college leagues have a limit of a -3 drop. So if you have a 32 inch bat, the lightest it can weigh is 29 ounces.
Also high school and college bats are required to comply with what is called the BESR (ball exit speed ratio) rule. This means that the ball cannot exit the bat more than a certain speed, and the barrel of the bat cannot be anymore than 2 5/8."