Bat Size Calculator Baseball & fastpitch softball bat length, weight and drop by age, height and weight.
Enter your hitter’s age, height and weight. You’ll get a starting bat length, a weight and drop range for the age, which certification stamp to look for, and three quick tests to confirm the fit.
- Baseball + fastpitch
- Ages 4–22
- Free · no sign-up
Find the right bat size
Takes about 20 seconds. Nothing is saved or sent anywhere.
How to size a bat (and why lighter usually wins)
Bat length comes from height and weight. Bat weight comes from strength. The calculator uses a published bat-sizing chart for length, then the typical drop for your hitter’s age to get a weight range.
I’ve watched more swings ruined by the wrong bat than by almost any mechanical flaw. A bat that’s too long or too heavy makes the hitter late, drags the barrel under the ball and builds a long swing to fight the weight. Bat speed is one of the things AHD hitters build on purpose, along with Mechanically Advantaged Angles (MAA), and the wrong bat steals both.
The three backyard tests
- Arm test (length): knob at the center of the chest, bat straight out to the side. If the fingertips reach the end of the barrel, the length fits.
- Hold-it-out test (weight): hold the bat by the handle, arm straight out at shoulder height. If the barrel drops before 30–45 seconds, it’s too heavy.
- Speed check: five swings with the bat, five with one an ounce or two lighter. If the lighter one is clearly quicker and on time, buy the lighter one.
Typical drop by age
| Age | Baseball (typical) | Fastpitch softball (typical) |
|---|---|---|
| 4–6 | -12 (tee ball, 26" max) | -11 to -13 · 24–26" |
| 7–9 | -10 to -11 | -10 to -13 · 26–29" |
| 10–13 | -10 | -10 to -12 (10–11) · -9 to -11 (12–14) |
| 14–15 | -5 (travel/Senior League) or -3 BBCOR in high school | -9 to -11 |
| High school & college | -3 (BBCOR) | -8 to -10 · 32–34" |
Always check your league’s rules before you buy. Little League, travel organizations, high school and college each require a specific stamp on the bat.
Sources: Baseball Monkey: Baseball bat size chart · Baseball Monkey: Fastpitch softball bat guide · Little League bat rules
Training guide
What it trains
Choosing the right bat length, weight and drop for your height, weight, age and league.
Who it’s for
Parents buying a bat, and players moving up to a new league or bat standard.
How to get better
- A bat you can control beats a bat that’s too long or heavy.
- Check your league’s bat stamp rules before you buy.
- Swing a few sizes if you can and pick the one that stays fast.
- A new bat doesn’t fix a swing. Build the swing first.
Read more on the Backspin Blog
- Baseball Bat Size Chart: By Age, Height & Weight
- Softball Bat Size Chart: Fastpitch by Age & Height
- $500 Bats Don’t Build Hitters: Youth Baseball Costs
- Bat Speed by Age: Baseball & Softball Chart (2026)
Next step: run the free Hitter Combine to find your #1 priority, or train this skill start to finish in the Athletic Development course.
Questions
What size bat should my child use?
Start with the chart: height and weight give the length, and age gives a typical drop (length minus weight). Then confirm it with the arm test and the hold-it-out test. Between two sizes, go shorter and lighter.
What does bat drop mean?
Drop is the bat’s length in inches minus its weight in ounces. A 30-inch, 20-ounce bat is a -10. Bigger drops are lighter; drops get smaller as players get older and stronger, down to -3 for BBCOR bats in high school and college baseball.
Is it bad to use a bat that is too heavy?
Yes. A bat that’s too heavy makes a hitter late, drops the barrel and teaches long, slow habits. A slightly lighter bat the hitter can control and swing fast almost always produces better contact.
What bat is legal for high school baseball?
High school and college baseball require BBCOR-certified bats, which are always -3. Little League Senior League also requires BBCOR for non-wood bats.