Baseball Stats Explained: AVG, OBP, SLG, OPS, ERA, and WHIP With Examples
October 29, 2026
Batting average (AVG) is hits divided by at-bats. On-base percentage (OBP) = (H + BB + HBP) ÷ (AB + BB + HBP + SF). Slugging percentage (SLG) = total bases ÷ at-bats, where total bases = singles + 2 × doubles + 3 × triples + 4 × home runs. OPS is OBP plus SLG.
A hitter has 550 at-bats, 165 hits (100 singles, 35 doubles, 3 triples, and 27 home runs), 60 walks, 5 hit by pitch, and 5 sacrifice flies. AVG = 165 ÷ 550 = .300.
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Total bases = 100 + 2 × 35 + 3 × 3 + 4 × 27 = 100 + 70 + 9 + 108 = 287. SLG = 287 ÷ 550 = .522. OBP = (165 + 60 + 5) ÷ (550 + 60 + 5 + 5) = 230 ÷ 620 = .371. OPS = .371 + .522 = .893. Rough benchmarks in recent MLB seasons: league-average AVG about .245 to .250, OBP about .315 to .320, SLG about .400 to .415, and OPS around .720 to .735. An OPS above .900 is excellent, and above .800 is above average. Park effects and eras differ, so compare with the league average (OPS+ adjusts for that).
| Stat | Calculation | Result |
|---|---|---|
| AVG | 165 / 550 | .300 |
| OBP | 230 / 620 | .371 |
| SLG | 287 / 550 | .522 |
| OPS | .371 + .522 | .893 |
Pitching Stats
ERA (earned run average) = 9 × earned runs ÷ innings pitched. With 62 earned runs in 180 innings, ERA = 9 × 62 ÷ 180 = 3.10. WHIP = (walks + hits) ÷ innings pitched; with 50 walks and 150 hits in 180 innings, WHIP = 200 ÷ 180 = 1.11. Typical league ERA is about 4.00 to 4.30 and WHIP about 1.28 to 1.32; an ERA below 3.00 and a WHIP below 1.10 are elite. Innings are written with thirds, so 180.1 means 180⅓ innings; convert before dividing.
Why OBP and SLG Matter
Batting average ignores walks and extra-base hits. Two players with the same AVG can contribute very differently: a .300 hitter with few walks and singles is less valuable than a .270 hitter with 90 walks and 40 home runs. OPS combines getting on base with power, and correlates well with scoring runs, though it overweights OBP less than it should; weighted on-base average (wOBA) assigns run values to each outcome.
Limits
ERA depends on defense, ballpark, and sequencing luck. FIP (fielding independent pitching) focuses on strikeouts, walks, and home runs. Small samples distort every stat early in a season. Use rates alongside playing time.
Frequently Asked Questions
How is OBP calculated?
(Hits + walks + hit by pitch) ÷ (at-bats + walks + hit by pitch + sacrifice flies).
What is OPS?
On-base percentage plus slugging percentage.
How is ERA calculated?
9 × earned runs ÷ innings pitched.
What does WHIP measure?
Walks plus hits allowed per inning pitched.
Why is AVG incomplete?
It ignores walks and the type of hit.