How this instrument works
Slugging percentage (SLG) measures the total bases a batter earns per at bat. A single is worth 1 base, a double 2, a triple 3, and a home run 4; add up every base earned across a season and divide by at bats, and the result is slugging percentage. Unlike batting average, which treats every hit identically, slugging percentage rewards extra-base power directly in the calculation itself.
This calculator takes total bases as a direct input rather than asking for singles, doubles, triples, and home runs separately, which keeps it useful when you already have a total-bases figure from a box score or stat page and just need to divide by at bats. Total bases itself is simply 1B + 2B x 2 + 3B x 3 + HR x 4 — this instrument skips straight to the division once you have that sum.
Despite the name, slugging percentage routinely exceeds 1.000 (or '100%'), which trips up newcomers expecting it to behave like a true percentage. A batter who homers in every single at bat would earn 4 total bases per at bat, for a slugging percentage of 4.000 — the name is a historical holdover, not a literal percentage bounded at 100.
SLG is most useful paired with on-base percentage rather than read alone, since it says nothing about how often a batter reaches base at all — only how many bases they earn on the at bats that produce a hit. That pairing is exactly what OPS (on-base plus slugging) combines into a single number, which is why the two stats are usually reported side by side.
- Enter Total bases — the sum of all bases earned from hits (singles count 1, doubles 2, triples 3, home runs 4).
- Enter At bats — official at bats for the same period.
- Read Slugging percentage — the instrument divides total bases by at bats automatically.
- If you only have hit counts by type, add them up as 1B + 2B x 2 + 3B x 3 + HR x 4 first to get total bases before entering it here.
- Compare the result to a league-average benchmark of roughly .400-.420 in modern MLB rather than judging the number in isolation.
Worked example — 250 total bases, 550 at bats
A batter racks up 250 total bases across 550 at bats over a season. Slugging percentage is 250 / 550 = 0.454545, typically written as .455 — a solid, roughly above-average power season for a modern MLB regular.
For context, if all 250 of those total bases had come from singles alone, the batter would have needed exactly 250 hits in 550 at bats — a .455 batting average, extraordinarily high. Because real total-base totals mix in doubles, triples, and home runs, a .455 slugging percentage is achievable with a far more ordinary hit total once extra-base hits are counted at their higher weight.
Questions
Why isn't slugging percentage capped at 1.000 like a real percentage?
Because it measures total bases per at bat, and a single at bat can produce up to 4 bases via a home run. A batter who homered in every at bat would post a slugging percentage of 4.000. The name comes from an older baseball usage of 'percentage' to mean any decimal-formatted rate stat, not a value bounded between 0 and 1 the way a literal percentage would be.
What's considered a good slugging percentage?
In modern MLB, league-average slugging percentage typically sits around .400 to .420. A good regular usually slugs in the .450-to-.500 range, and anything above .550 for a full season marks genuine power-hitting production, with the very best sluggers occasionally reaching .600 or higher. Slugging percentage tends to run noticeably higher than batting average for the same player once extra-base hits are weighted in.
How do I calculate total bases if I only have hit counts by type?
Add up singles worth 1 base each, doubles worth 2, triples worth 3, and home runs worth 4: total bases = 1B + (2B x 2) + (3B x 3) + (HR x 4). For example, 20 singles, 10 doubles, 2 triples, and 15 home runs gives 20 + 20 + 6 + 60 = 106 total bases. Enter that sum here along with at bats to get slugging percentage.
How is slugging percentage different from batting average?
Batting average counts every hit as worth exactly one toward the numerator, regardless of whether it was a single or a home run, then divides by at bats. Slugging percentage instead weights hits by how many bases they're worth before dividing by at bats. A hitter who mostly singles can have a high batting average but a modest slugging percentage, while a power hitter with fewer overall hits but more extra-base ones can slug much higher than their batting average alone would suggest.
How does slugging percentage combine with OPS?
On-base plus slugging (OPS) is simply on-base percentage added to slugging percentage, giving a single number that rewards both reaching base and hitting for power. Once you have a slugging percentage figure from this calculator, this site's OPS instrument lets you add an on-base percentage straight to it to get the combined stat.