Enter a batter's At-Bats, Singles, Doubles, Triples, and Home Runs to compute their Slugging Percentage (SLG) — the standard measure of a hitter's power production. You'll see the SLG value, a performance rating, and a breakdown of how each hit type contributes to total bases.
Slugging Percentage (SLG)
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Total Bases
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Performance Rating
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Total Hits
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Batting Average (H/AB)
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Slugging Percentage (SLG) measures a batter's hitting power by calculating the average number of bases earned per at-bat. Unlike batting average, it weights extra-base hits more heavily — doubles count 2x, triples 3x, and home runs 4x — making it a stronger indicator of offensive production. It is expressed as a decimal rather than a true percentage.
The formula is: SLG = (1B + 2×2B + 3×3B + 4×HR) / AB. You multiply each hit type by the number of bases it earns, sum those values to get Total Bases, then divide by the number of At-Bats. For example, a player with 100 singles, 25 doubles, 3 triples, and 20 home runs in 500 at-bats has a SLG of (100 + 50 + 9 + 80) / 500 = 0.478.
As a general benchmark: below 0.300 is poor, 0.300–0.399 is below average, 0.400–0.449 is average, 0.450–0.499 is above average, 0.500–0.549 is great, and above 0.550 is elite. The MLB all-time single-season record is 0.863 by Barry Bonds in 2001.
Batting Average (BA) treats all hits equally — a single counts the same as a home run. Slugging Percentage goes further by weighting hits by the number of bases earned, so it better reflects a player's power and run-producing ability. A player can have a high BA but low SLG if they mostly hit singles, or a low BA but high SLG if they hit for power.
Mathematically, yes — a player who hit a home run in every single at-bat would have a SLG of 4.000. However, in practice SLG never reaches 1.000 over a full season. The highest ever recorded over a meaningful number of at-bats is Barry Bonds' 0.863 in 2001.
No. Walks (and hit-by-pitches, sacrifices, etc.) are not counted as at-bats, so they do not factor into SLG at all. This is one reason On-Base Plus Slugging (OPS) exists — it combines On-Base Percentage (which includes walks) with SLG for a more complete picture of a hitter's value.
Isolated Power (ISO) measures a batter's raw extra-base-hit power by removing singles from the equation. It is calculated as ISO = SLG − Batting Average. A high ISO indicates a player generates many extra bases, regardless of their overall hit rate. While SLG reflects total offensive production per at-bat, ISO isolates pure power hitting.
The MLB league-average SLG has historically hovered around 0.400–0.430, though it fluctuates year to year based on era, rule changes, and offensive trends. A SLG above 0.450 is generally considered above average for a full-time player in the modern game.