Slugging Percentage Calculator

Slugging percentage is how many bases a hitter averages per at-bat

Slugging percentage (SLG) is total bases divided by at-bats. A single counts as one base, a double as two, a triple as three and a home run as four, so unlike batting average, which counts every hit as one, it rewards how far each hit took the runner. The MLB Glossary defines slugging percentage as the total number of bases a player records per at-bat, and Official Baseball Rule 9.21(c) tells scorers to divide total bases on hits by the number of at-bats.

In the 2026 MLB regular season, Yordan Alvarez (HOU) had 567 at-bats with 102 singles, 34 doubles, 1 triple and 42 home runs, which adds up to 341 total bases. Dividing 341 by 567 gives a slugging percentage of .601, the highest among the 135 qualified MLB hitters. His .316 batting average was also the best of the group. The runner-up in slugging, Pete Crow-Armstrong (CHC), hit .280 and slugged .570.

What batting average alone leaves out

Batting average counts a bunt single and a home run the same way. Because slugging percentage counts the type of hit, it helps with questions like these.

• Who hits for more damage: Luis Arraez (PHI) hit .310, third in batting average among 2026 MLB qualified hitters, but slugged only .419, 73rd of 135. Crow-Armstrong hit .280 and slugged .570, second. Choosing by average alone would reverse the two.
• Two hitters with the same slugging, built differently: Munetaka Murakami (CWS) slugged .478 as a .207 hitter averaging 2.31 total bases per hit. Jake McCarthy (COL) slugged .475 as a .291 hitter averaging 1.64. One hit rarely and far, the other hit often and shorter.
• Setting a lineup or a fantasy roster: A hitter who drives in runners with extra-base hits shows it in slugging far more than in average. When you weigh candidates for the middle of the order, compare slugging and total bases per hit side by side.
• Looking at pitchers: Applying the same formula to the hits a pitcher allows gives slugging percentage against, which the MLB Glossary also lists.

How to use the calculator

1. Choose the league to compare with (KBO, MLB or NPB). The league average and the hitters on the ranking ladder switch to that league's 2026 regular season.
2. Pick a player under 'Load a 2026 qualified hitter' to fill the ledger with that player's line. To calculate your own, enter at-bats, hits, doubles, triples and home runs in the ledger.
3. Enter total hits in the Hits field, extra-base hits included. Singles are filled in automatically as hits minus doubles, triples and home runs. Walks, hit-by-pitches and sacrifices are not at-bats, so leave them out; empty fields count as 0. You can copy AB, H, 2B, 3B and HR straight from a stats page such as Baseball-Reference.
4. On each ledger row, read 'count × multiplier = bases' and the bar. The tick on the bar is the number of bases a league-average hitter would get in the same at-bats, and the number on the right is the difference.
5. On the ranking ladder, see the dot strip of every qualified hitter and the SLG breakdown of the hitters just above and below your line. The reading lines underneath give the rank, the AVG × total bases per hit profile, the home runs needed for the next mark and the extra-base hit share. Copy result and Copy link reopen the same calculation.

How slugging percentage is calculated

1. Singles = hits − doubles − triples − home runs
2. Total bases = singles + 2 × doubles + 3 × triples + 4 × home runs
3. Slugging percentage = total bases ÷ at-bats, rounded to three decimals the way box scores do, for example .601.
4. The same value splits into batting average × total bases per hit. Total bases per hit is total bases ÷ hits: 1.00 if every hit is a single, 4.00 if every hit is a home run.

Here is Alvarez's line laid out as a ledger. The right-hand column shows what a league-average 2026 MLB hitter would produce in the same 567 at-bats: the league's base mix by hit type, scaled to 567 at-bats and rounded to whole numbers so that the total is the unrounded league SLG (.4005) × 567 = 227.1, rounded to 227.

Of the 114-base gap between the two, 91 bases come from home runs, while triples are 4 bases short. Alvarez's slugging comes from home runs, not from a pile of singles.

League averages and qualified hitters (2026 regular season)

League averages are computed from the combined totals of every team in the league. Pitchers bat in the NPB Central League in 2026, so their batting lines are removed from the Central League figures.

The KBO league-average slugging percentage rose from .389 in 2025 to .404 in 2026, a gain of .015, and the home run share of total bases grew from 25.0% to 27.3%. MLB slipped slightly from .404 to .400. The three leagues sit close together, between .369 and .404, but 34.1% of MLB total bases come from home runs, against 27.3% in the KBO and 27.6% in the NPB, so MLB leans harder on the long ball.

What is a good slugging percentage?

There is no official rating scale for slugging percentage. The FanGraphs Library gives rough benchmark tables for ISO and wOBA but not for SLG. This calculator therefore does not attach labels and instead ranks a line among the qualified hitters of the same league. In the 2026 regular season, the rough landmarks are these.

• .500 or higher: Only 11 of 49 KBO hitters, 14 of 135 MLB hitters and 8 of 45 NPB hitters got there. In MLB that is about the top 10% of qualified hitters.
• Around .430: The median of qualified hitters is .426 in the KBO and .427 in MLB. In the NPB it is .392.
• Around .400: The league-wide average (KBO .404, MLB .400, NPB .369). It includes the plate appearances of players who did not qualify, so it sits below the median of qualified hitters.
• Under .400: 18 KBO hitters, 43 MLB hitters and 25 NPB hitters. Some of them keep a lineup spot with on-base skills or defense, so slugging alone should not decide a hitter's value.

Same slugging, different routes: AVG × total bases per hit

Slugging percentage is batting average times total bases per hit, because total bases ÷ at-bats = (hits ÷ at-bats) × (total bases ÷ hits). That is why a hitter who reaches a given slugging by hitting often and one who reaches it by hitting far can sit side by side. The calculator's reading line compares both values with the league average and sorts each line into one of four profiles (batting average to three decimals, bases per hit to two).

MLB has 32 power-type hitters, far more than the KBO (4) or NPB (3). Among 2026 MLB qualified hitters, the highest total bases per hit belonged to Munetaka Murakami (CWS) at 2.31, but his .207 average held his slugging to .478. At the other end, Chandler Simpson (TB) hit .306 yet averaged only 1.16 total bases per hit, so he slugged .356, 123rd of 135.

Slugging versus other batting stats

A hitter with high slugging and a low on-base percentage gets a lower OPS than the slugging suggests, and a hitter with many singles and walks shows their value in on-base percentage more than in slugging. To compare hitters with a single number, look at OPS or wOBA, and use OPS+ to adjust for league and ballpark.

Common mistakes

• Reading it as a percentage: A slugging percentage of .601 does not mean 60.1%. It means the hitter averaged 0.601 bases per at-bat. The word 'percentage' in the name is misleading, because the stat is an average and can exceed 1.000.
• Dividing by plate appearances: The denominator is at-bats, not plate appearances. Under Official Baseball Rule 9.02(a)(1), sacrifice bunts, sacrifice flies, walks, hit-by-pitches and reaching on interference are not at-bats.
• Entering only singles in the Hits field: H in a stats table is all hits, extra-base hits included. If you enter only the number of singles, the extra-base hits get subtracted twice, which gives an error or a lower slugging percentage.
• Averaging game-by-game slugging: To combine games or seasons, divide the sum of total bases by the sum of at-bats instead of averaging the percentages. A 4-at-bat game with 2 home runs (2.000) and 40 at-bats with 12 total bases (.300) average out to 1.150, but the real slugging is (8 + 12) ÷ 44 = .455.
• Multiplying rounded values: Jake McCarthy's .291 average times 1.64 bases per hit is .477, but his real slugging is 260 ÷ 547 = .475. To check the formula, use the unrounded bases and at-bats.

Highest slugging percentages ever

The Baseball-Reference single-season leaderboard also includes Negro Leagues play, so its first place is Josh Gibson's .982 in 1937 (192 PA). Among American and National League seasons, Bonds's .863 in 2001 is the highest. The second-best NPB season is Randy Bass's (Hanshin) .777 in 1986, and the third is Hiromitsu Ochiai's (Lotte) .763 in 1985. In the 2026 regular season, no hitter in any of the three leagues came close to these marks (KBO best .647, MLB .601, NPB .609).

Limitations

• It ignores walks: Slugging percentage only deals with hits, so it misses the value of a hitter who draws many walks. The MLB Glossary notes that, unlike on-base percentage, it leaves walks and hit-by-pitches out of the formula. Read it next to on-base percentage, or use OPS or wOBA.
• Bases are not weighted by run value: Slugging counts a home run as four singles. The MLB Glossary says a double is not worth exactly twice a single in terms of scoring, yet it still lists slugging percentage among the good measures of power. wOBA is the stat that weights each outcome by run value.
• It does not adjust for ballpark or run environment: The same slugging is worth less in a hitter-friendly park or in a high-power season. The calculator only compares with the average of the same league and season; to adjust for ballpark, look at a stat such as OPS+.
• Small samples swing widely: FanGraphs puts the point at which SLG becomes meaningfully stable at about 320 at-bats. With fewer at-bats, one or two home runs can move the value a lot, so the calculator adds a notice to its verdict line.
• The "to the next mark" row is the minimum number of home runs (or doubles) if every following at-bat produced one. It is not a projection.
• NPB 2026 league totals were rebuilt from Sportsnavi team player stats plus players traded during the season, because the official site (npb.jp) could not be reached. Compared with the team pitching totals, the rebuilt totals are 31 plate appearances and 6 hits short, with the same number of home runs. No NPB 2025 average is shown because the Central League pitchers' batting totals could not be obtained.

As of: the definition and rules were checked on 2026-10-23 against the MLB glossary, the Official Baseball Rules and FanGraphs Library, and the records were checked the same day against Baseball-Reference, NPB official records (archived, as of the end of the 2025 season) and Namu Wiki. League totals and qualified hitters were computed from the final 2026 regular-season records of the KBO record site, the MLB Stats API and NPB records, downloaded on 2026-10-22.

Sources

• 01MLB Glossary: Slugging Percentage (SLG)Definition (total bases per at-bat), formula (1B + 2B×2 + 3B×3 + HR×4) ÷ AB, walks and hit-by-pitches excluded, slugging against
• 02Official Baseball Rules 20259.21(c) slugging percentage, 9.02(a)(1) plays that are not at-bats, 9.22(a) qualifying plate appearances (team games × 3.1)
• 03FanGraphs Library: Sample SizeSample at which hitting stats stabilize: SLG 320 AB
• 04KBO Record Room: team hitting2025 and 2026 regular-season totals for AB, H, 2B, 3B and HR across 10 teams
• 05KBO Record Room: player hitting2026 regular season, 49 hitters with 446 or more plate appearances
• 06MLB Stats API: team hitting2025 and 2026 regular-season totals for 30 teams
• 07MLB Stats API: 2026 qualified hitters135 hitters with 502 or more plate appearances
• 08NPB: 2026 Central League qualified hitters (archived)With the Pacific League table (bat_p), 45 qualified hitters; archived 2026-10-08
• 09Sportsnavi (Yahoo! JAPAN): NPB team battingLeague totals rebuilt by summing the 2026 player lines of all 12 NPB teams
• 10Baseball-Reference: single-season slugging leadersNo. 1 Josh Gibson 1937 .982 (192 PA), No. 5 Barry Bonds 2001 .863, career leader Babe Ruth .690
• 11NPB: season slugging records (archived)Through the 2025 season: Balentien 2013 .779, Bass 1986 .777, Ochiai 1985 .763
• 12Namu Wiki: Slugging percentage (Korean)KBO season leader Thames 2015 .790, career leader Lee Seung-yuop .572 (3,000+ PA), NPB career leader Sadaharu Oh .634

Frequently asked questions

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