How slugging percentage is calculated
SLG weights hits by total bases: SLG = (1B + 2×2B + 3×3B + 4×HR) ÷ at-bats. With 10 singles, 5 doubles, 1 triple and 4 home runs that is 10 + 10 + 3 + 16 = 39 total bases over 50 at-bats = .780.
Enter only singles in the singles box. A frequent mistake is entering total hits, which double-counts the doubles, triples and home runs: if a box score shows 20 hits including 5 doubles, 1 triple and 4 home runs, the singles figure is 20 − 10 = 10.
Keep the batting average calculator nearby for the rest of the same job.
How to use this calculator
Enter the count of singles, doubles, triples, home runs and total at-bats. The result is SLG to three decimals. For scoring output, see the points per game calculator.
Despite the name, slugging percentage is not a percentage — it is total bases per at-bat and can exceed 1.000. The theoretical maximum is 4.000, a home run in every at-bat, and the figure is written with a leading decimal point as .780 rather than as 78%.
What slugging percentage tells you
SLG measures power, not just contact. A .780 mark is elite — league-average SLG sits closer to .400. Because it credits extra-base hits, two players with the same batting average can have very different slugging numbers.
Context matters as much as the number: 39 total bases in 50 at-bats is .780, but the same 39 bases spread over 100 at-bats is .390, close to league average. Isolated power (ISO) strips singles out by subtracting batting average from SLG, giving another view of pure extra-base ability.
The same numbers feed straight into the on-base percentage calculator.
Frequently asked questions
- How do I calculate slugging percentage?
- Add total bases (1×singles, 2×doubles, 3×triples, 4×home runs) and divide by at-bats. 39 ÷ 50 = .780.
- What is a good slugging percentage?
- Around .450 is solid and .550+ is excellent in MLB. League average is roughly .400.
- How is SLG different from batting average?
- Batting average counts every hit equally; slugging weights extra-base hits, so it reflects power.
- What if at-bats is zero?
- Slugging percentage is undefined with zero at-bats, so the calculator shows a dash until you enter a positive number.
- Do walks and sacrifices count in slugging percentage?
- No — walks, hit by pitch and sacrifice flies are not at-bats, so they never enter the SLG calculation at all. That is why OPS is usually quoted alongside it: slugging measures power per at-bat, while on-base percentage captures the walks.