BABIP is the share of balls in play that fall for hits
BABIP (Batting Average on Balls In Play) keeps only the batted balls the defense had a chance to field and asks how many of them became hits. The formula is (H − HR) ÷ (AB − SO − HR + SF). MLB's official glossary says it leaves out outcomes the opposing defense can't affect, namely home runs and strikeouts, and gives a 2-for-5 example with one home run and one strikeout. That hitter put three balls in play and one fell for a hit, so his BABIP is .333.
Type in one line of a box score and the calculator shows the BABIP, where it came from (what gets removed and what stays in play), how far it sits from the league average, and how much a sample this size can swing on luck alone. The 2026 regular-season league averages are MLB .290, NPB .288 and KBO .317. It also works for a pitcher's BABIP against, using batters faced, and you can save several players or periods to a list and compare them on the same chart.
Why look at BABIP on its own
Batting average mixes strikeouts and home runs into one number, so when it jumps or sinks it is hard to tell whether the cause is contact skill, more power, or balls in play that happened to find holes. BABIP isolates that last part, which is why it comes up in situations like these.
- An early-season average that looks too good (or too bad): a hitter at .325 after 20 games with a .393 BABIP may simply have had more balls in play fall than usual. The first screen of the calculator is exactly this case, and it also shows that over 61 balls in play even an average hitter's BABIP can land anywhere from .176 to .403.
- A pitcher's ERA has gotten worse: FanGraphs explains that a pitcher has little control over what happens once a ball is in play and that pitcher BABIP is heavily influenced by defense and luck. If the BABIP against is well above average, part of the extra runs may trace back to defense and luck.
- Comparing this year with a career line: as the MLB glossary's Mike Trout example shows, some hitters hold a BABIP above the league average for years. Put the player's career BABIP in as the comparison base and you are measuring him against his own usual level instead of the league.
- Fantasy baseball decisions: when you are weighing a hot or cold streak, the BABIP and the size of the sample behind it tell you how much of the streak to trust.
- Little League, high school and rec league scorebooks: if your sheet only lists at-bats, hits, home runs, strikeouts and sacrifice flies, you can get the number without building a spreadsheet.
How to use it
- Pick batter or pitcher. A batter takes five fields: at-bats (AB), hits (H), home runs (HR), strikeouts (SO) and sacrifice flies (SF). A pitcher takes six: batters faced (TBF), hits allowed, home runs allowed, strikeouts, walks (BB) and hit batters (HBP). Empty fields count as 0, and you can type commas such as 1,234.
- Read the split bar. Hits in play, outs in play and the removed results (home runs and strikeouts, plus walks and hit batters for a pitcher) are drawn by length. The brackets above mark the denominator (balls in play) and the numerator (hits in play), and the formula under the bar uses your own numbers.
- Choose a comparison base. Pick the 2026 or 2025 regular-season average for MLB, NPB or KBO, or choose "Enter my own" and type a value such as .312, for example a player's career BABIP. If you pick a pitcher, the averages in the list switch to the pitcher-style values, and if you choose "Enter my own", "average" in the sentence becomes "base".
- Read the funnel and the sentence beneath it. The dark band is the 68% range, the light band is the 95% range, and the orange dot is your record. A dot inside the light band is a value an average player could produce on luck alone. A dot outside it is rare for luck alone.
- Save records to the list. "Save this record" leaves a lettered dot (A to F) on the funnel, and tapping a record in the list reloads it. The list stays in this browser only, and "Copy link" copies an address that holds the current record.
How BABIP is calculated
The numerator is H − HR. Hits include everything from singles to home runs, so subtracting home runs leaves only the hits that were put into the field of play. The denominator is AB − SO − HR + SF. According to the MLB glossary, an at-bat is charged when a batter reaches on a hit, an error or a fielder's choice, or makes an out on a batted ball that is not a sacrifice, and a walk is not an at-bat. So taking strikeouts (no batted ball) and home runs (not fieldable) out of at-bats leaves the balls in play. A sacrifice fly is a ball the outfielder caught, but it doesn't count as an at-bat, so it is added back to the denominator.
A pitcher's BABIP against starts from batters faced (TBF) and subtracts walks, hit batters, strikeouts and home runs allowed. In principle sacrifice bunts should come out of the denominator too, but pitching tables on league sites often have no at-bat or sacrifice bunt columns. FanGraphs says it cannot remove sacrifice bunts from its pitcher data and describes this as "a data problem on our end", not a disagreement about method. This calculator keeps them for the same reason, so sacrifice bunts and sacrifice flies stay in play, and the league average used for pitchers is recalculated the same way, with sacrifice bunts added to the denominator (the second table in the league average section below). The result is rounded to three decimal places, and because it is below 1 the leading zero is dropped, as in baseball notation (.393).
| Line | Numerator | Denominator | BABIP |
|---|---|---|---|
| MLB glossary example: 2-for-5, 1 HR, 1 SO | 2 − 1 = 1 | 5 − 1 − 1 + 0 = 3 | .333 |
| First 20 games: 80 AB, 26 H, 2 HR, 18 SO, 1 SF | 26 − 2 = 24 | 80 − 18 − 2 + 1 = 61 | .393 |
| Full season: 580 AB, 192 H, 12 HR, 90 SO, 5 SF | 192 − 12 = 180 | 580 − 90 − 12 + 5 = 483 | .373 |
| Pitcher season: 680 TBF, 175 H, 15 HR, 140 SO, 48 BB, 7 HBP | 175 − 15 = 160 | 680 − 48 − 7 − 140 − 15 = 470 | .340 |
League average BABIP (2025 and 2026 regular seasons)
The MLB glossary says the league average BABIP is typically around .300. It does vary by league and by year, so the table below applies the same formula to each league's official regular-season totals. MLB came in at .290 or .291 in both seasons, NPB at .288 to .292, and KBO above .310 in both. A .330 BABIP is .040 above the MLB 2026 average but only .013 above the KBO 2026 average, so choose the comparison base that matches the league and season the player actually played in.
| League and season | AB | H | HR | SO | SF | In play | BABIP |
|---|---|---|---|---|---|---|---|
| MLB 2026 | 163,329 | 39,849 | 5,575 | 40,700 | 1,298 | 118,352 | .290 |
| MLB 2025 | 163,664 | 40,138 | 5,650 | 40,645 | 1,307 | 118,676 | .291 |
| NPB 2026 | 57,180 | 13,742 | 1,426 | 13,430 | 374 | 42,698 | .288 |
| NPB 2025 | 57,532 | 14,053 | 1,096 | 12,475 | 379 | 44,340 | .292 |
| KBO 2026 | 49,548 | 13,277 | 1,366 | 11,054 | 437 | 37,565 | .317 |
| KBO 2025 | 49,021 | 12,824 | 1,191 | 11,024 | 451 | 37,257 | .312 |
For pitchers, the same totals are used with sacrifice bunts added to the denominator. Because the pitcher calculation keeps sacrifice bunts in play, the league average has to be computed the same way, or an average pitcher would lean toward looking "below average". The more sacrifice bunts a league has, the bigger the gap: NPB 2025 drops from .292 to .285.
| League and season | Sacrifice bunts | Denominator | Pitcher-style average | Batter-style |
|---|---|---|---|---|
| MLB 2026 | 682 | 119,034 | .288 | .290 |
| MLB 2025 | 560 | 119,236 | .289 | .291 |
| NPB 2026 | 868 | 43,566 | .283 | .288 |
| NPB 2025 | 1,113 | 45,453 | .285 | .292 |
| KBO 2026 | 590 | 38,155 | .312 | .317 |
| KBO 2025 | 594 | 37,851 | .307 | .312 |
The MLB rows are the 30-team totals, and Baseball-Reference's league totals match the MLB official statistics. The NPB rows combine the 12 teams of the Central and Pacific Leagues. Split by league, 2026 is Central .288 and Pacific .289, and 2025 is Central .290 and Pacific .294. KBO sacrifice bunts are the SAC total in the team hitting records, and KBO strikeouts are the sum of the strikeouts in the team pitching records, which gives the same figure as the league's batting strikeouts.
What a high or low BABIP can mean
FanGraphs names three things that move BABIP: defense, luck and talent level. The harder a ball is hit, the more likely it is to fall in for a hit, and line drives go for hits more often than groundballs, which go for hits more often than flyballs. A hitter can influence his BABIP through how he hits the ball, but FanGraphs says a pitcher has little control over the result once the ball is in play. Skill still plays a role, though. The MLB glossary points to Clayton Kershaw's career BABIP against of .270 and Mike Trout's career BABIP of .348, both as of the end of the 2019 season.
| Situation | What to check first |
|---|---|
| Hitter BABIP is high | Whether he hit a lot of hard-hit balls and line drives, and whether his career BABIP is high too. With a small sample, luck carries a lot of the weight. |
| Hitter BABIP is low | Whether he hit more flyballs or weak contact, whether shifts kept meeting his batted balls (an example FanGraphs gives), and whether the sample is small. |
| Pitcher BABIP against is high | Whether the defense behind him was poor and whether the sample is small. If it is above average but still inside the luck range, consider that it may move back toward the average. |
| Pitcher BABIP against is low | Whether he steadily gets weak contact (look at his career numbers) or got help from his defense. A low value over a few starts may not last. |
Small samples let luck in
Picture a player whose chance of any ball in play falling for a hit equals the league average. His BABIP still moves around from sample to sample like a run of coin flips, and the spread (the standard deviation) is √(average × (1 − average) ÷ balls in play). For a .300 player the table below shows a 95% range of .210 to .390 over 100 balls in play, and even at 400 it is .255 to .345. The calculator's funnel redraws this range for whichever league average you pick.
| Balls in play | 68% range | 95% range |
|---|---|---|
| 50 | .235~.365 | .173~.427 |
| 100 | .254~.346 | .210~.390 |
| 200 | .268~.332 | .236~.364 |
| 400 | .277~.323 | .255~.345 |
| 820 | .284~.316 | .269~.331 |
| 2,000 | .290~.310 | .280~.320 |
FanGraphs' sample-size guide, drawing on Russell Carleton's research, puts the point where two samples of the same size correlate at 0.7 at 820 balls in play for hitter BABIP and 2,000 for pitcher BABIP. The BABIP article on the same site translates that into roughly two seasons for a hitter and roughly three seasons for a starting pitcher, while adding that there is no magic threshold at which BABIP suddenly becomes reliable. The "stabilizes at" row and the dotted line in the calculator are a reference for how far along you are toward those numbers.
Common mistakes
- Not removing home runs: in the early-season example, leaving home runs in both the numerator and the denominator gives 26 ÷ 63 = .413, higher than the real .393.
- Not removing strikeouts: keeping the 18 strikeouts in the denominator gives 24 ÷ 79 = .304, a low value that mixes in results with no ball in play.
- Forgetting the sacrifice fly: without adding the one sacrifice fly you get 24 ÷ 60 = .400. The more sacrifice flies a hitter has, the bigger the gap.
- A strikeout where the batter reaches first: according to the MLB glossary, if the catcher fails to hold the third strike and the batter reaches first, it is still scored as a strikeout. For BABIP it comes out like any other strikeout.
- Reaching on an error: it counts as an at-bat but not as a hit, so for BABIP it sits in the denominator like an out in play.
- Entering batters faced in the at-bats field: in batter mode, putting batters faced in the at-bats field mixes walks and hit batters into the denominator. For a pitcher's record, choose "Pitcher" and enter walks and hit batters separately.
Limits
- The 68% and 95% ranges assume every ball in play has the same chance of becoming a hit and that they don't affect each other. Real opposing pitchers, ballparks and defenses change every night, so the real swing can be wider.
- A value outside the range does not automatically mean skill. BABIP alone can't tell you whether the gap from the league average comes from contact quality, defense or ballpark.
- The calculator takes no batted-ball data such as exit velocity or launch angle, so it does not estimate an expected BABIP from contact quality.
- The pitcher calculation keeps sacrifice bunts in play, so the third decimal can differ slightly from a BABIP against on a site that removes them in principle; the comparison average is matched to the same method instead. Catcher's interference is rare and is not removed separately.
- League averages are full regular-season totals. To compare with the postseason, the minors or a specific ballpark or stretch, use "Enter my own".
- The comparison list lives only in this browser's storage and is never sent to a server. Clearing browser data clears the list.
As of The formula and explanations were checked on 2026-10-21 against the MLB glossary and the FanGraphs Library. League averages were calculated the same day from the 2025 and 2026 regular-season totals of the official KBO and NPB record rooms and Baseball-Reference (cross-checked with MLB official statistics).
Sources
- 01MLB Glossary — Batting Average on Balls in Play (BABIP)Definition and formula (H − HR)/(AB − K − HR + SF), the 2-for-5 example of .333, league average around .300, Kershaw .270 and Trout .348 (through 2019)
- 02FanGraphs Library — BABIPDefense, luck and talent level; line drives, groundballs and flyballs; about 800 balls in play for hitters and 2,000 for pitchers; sacrifice bunts cannot be removed from pitcher data (a data limit, not a method choice)
- 03FanGraphs Library — Sample SizeRussell Carleton's 0.7 correlation benchmark: hitter BABIP 820 BIP, pitcher BABIP 2000 BIP
- 04MLB Glossary — At-bat (AB)When an at-bat is charged; a walk is not an at-bat
- 05MLB Glossary — Sacrifice Fly (SF)A sacrifice fly does not count as an at-bat
- 06MLB Glossary — Strikeout (SO)Scored as a strikeout even if the batter reaches first on a dropped third strike
- 07KBO League — Team records (hitters)2025 and 2026 regular-season totals for the 10 teams: at-bats, hits, home runs, sacrifice bunts (SAC), sacrifice flies
- 08KBO League — Team records (pitchers)2025 and 2026 regular-season strikeout totals (used as the league strikeout total)
- 09NPB — 2026年度 セントラル・リーグ チーム打撃成績Central League, 6 teams: AB, H, HR, SO, sacrifice bunts (犠打), SF
- 10NPB — 2026年度 パシフィック・リーグ チーム打撃成績Pacific League, 6 teams; 2025 is on the same site's 2025 pages (tmb_c and tmb_p)
- 11Baseball-Reference — 2026 Major League Baseball Standard BattingLeague Totals row (2025 uses the same format on its own page), equal to the 30-team sum in MLB official statistics
Frequently asked questions
How do you calculate BABIP?
BABIP = (H − HR) ÷ (AB − SO − HR + SF). For example, a hitter with 80 at-bats, 26 hits, 2 home runs, 18 strikeouts and 1 sacrifice fly has a numerator of 26 − 2 = 24 and a denominator of 80 − 18 − 2 + 1 = 61, so 24 ÷ 61 = .393. The result is rounded to three decimal places.
What is a good BABIP, and what is the league average?
The MLB glossary says the league average BABIP is typically around .300. Recalculated from official league totals, the 2026 regular season is MLB .290, NPB .288 and KBO .317, and 2025 is MLB .291, NPB .292 and KBO .312. Compare a player with the average for the league and season he actually played in.
Is a high BABIP good or bad?
For a hitter it means more of his balls in play fell for hits, and for a pitcher it means more hits allowed. BABIP mixes defense, luck and talent, so a high value can be real skill, such as a hitter who regularly hits the ball hard, or it can be luck in a small sample. The fewer the balls in play, the larger the share luck carries.
Why are home runs taken out of BABIP when they are hits?
A home run leaves the park, so the defense has no chance to turn it into an out. BABIP looks at the share of fieldable balls in play that became hits, so home runs come out of both the numerator (hits) and the denominator (at-bats).
Why is the sacrifice fly added to the denominator?
A sacrifice fly is a ball in play that an outfielder catches, but under the rules it is not an at-bat. Using at-bats alone would leave that ball out, so it is added back to count every ball the defense handled. Sacrifice bunts are not part of the batter BABIP formula.
How many games does it take before BABIP can be trusted?
FanGraphs' sample-size guide puts the point where two same-size samples correlate at 0.7 at 820 balls in play for hitters and 2,000 for pitchers. FanGraphs' BABIP article gives roughly 800 and 2,000 and describes that as about two seasons for a hitter and about three for a starter. Even a .300 hitter can land anywhere from .210 to .390 over 100 balls in play, so read a few dozen games with plenty of room for luck.
How do you calculate a pitcher's BABIP against?
BABIP against = (H − HR) ÷ (batters faced − BB − HBP − SO − HR). In principle sacrifice bunts should come out of the denominator too, but league pitching tables often do not list them, so, like FanGraphs pitcher data, this calculator leaves them in. The comparison league average is recalculated the same way (MLB 2026 .288), so you can compute it from the numbers in a pitching table alone. For example, 680 batters faced, 175 hits, 15 home runs, 140 strikeouts, 48 walks and 7 hit batters give 160 ÷ 470 = .340.
How is BABIP different from batting average?
Batting average is hits divided by at-bats, so strikeouts and home runs are both in it. BABIP removes strikeouts and home runs and looks only at balls in play, so the same hitter gets a different number. A line of 26 hits in 80 at-bats is a .325 average, but taking out 2 home runs and 18 strikeouts and adding 1 sacrifice fly gives a BABIP of .393.