Baseball Stats Calculator — Batting Average, ERA, OBP, SLG, OPS and More

This calculator computes all major hitting stats (BA, OBP, SLG, OPS, Total Bases) and pitching stats (ERA, WHIP) from raw box score numbers. Enter your figures in the Hitting or Pitching tab and get instant results with MLB-calibrated performance ratings. Works for baseball and softball — adjust innings per game for 7-inning formats.

Hitting Stats

Batting Average (BA) = Hits ÷ At Bats

The most basic hitting stat. A .300 BA means you get a hit 30% of the time you put the ball in play. Simple, but it misses walks entirely — a player who walks 100 times looks the same as one who walks 10 times.

On-Base Percentage (OBP) = (Hits + BB + HBP) ÷ (AB + BB + HBP + SF)

OBP fixes what batting average misses — it counts every way a batter reaches base. A .400 OBP means the batter reaches base 40% of the time. Most coaches and front offices now value OBP more than BA because getting on base creates runs.

Slugging Percentage (SLG) = Total Bases ÷ At Bats

Where Total Bases = Singles + (2 × Doubles) + (3 × Triples) + (4 × Home Runs). SLG measures power. A single and a home run are the same in batting average — both are “hits.” In slugging, a home run is worth four times as much.

OPS (On-Base Plus Slugging) = OBP + SLG

The all-in-one hitting stat. OPS combines a batter’s ability to get on base AND hit for power into one number. It’s the fastest way to evaluate a hitter’s overall offensive contribution.

Total Bases = 1B + (2 × 2B) + (3 × 3B) + (4 × HR)

The raw counting stat behind slugging percentage. Total bases tells you exactly how many bases a player earned through hits alone.

Pitching Stats

ERA (Earned Run Average) = (Earned Runs × Game Innings) ÷ Innings Pitched

ERA tells you how many runs a pitcher allows per full game. An ERA of 3.00 means the pitcher allows 3 earned runs per 9 innings on average. “Earned” means runs that scored without errors.

WHIP (Walks + Hits per Inning Pitched) = (BB + Hits Allowed) ÷ Innings Pitched

WHIP measures how many baserunners a pitcher allows per inning. Lower is better. WHIP catches something ERA misses — a pitcher can have a decent ERA while putting runners on base constantly if they strand them.

MLB hitting benchmarks: .300+ BA is excellent, .400+ OBP is elite, .500+ SLG is excellent, .900+ OPS is All-Star level. Pitching benchmarks: below 2.50 ERA is elite, below 1.10 WHIP is excellent. High school and youth averages run higher than MLB because pitching is less dominant — context the level of play before comparing numbers.

Hitting Benchmarks

Context matters. These benchmarks are for MLB. High school and college averages run higher because pitching is less dominant.

Pitching Benchmarks

ERA can lie. A pitcher with a 3.50 ERA and a 1.40 WHIP is getting lucky — they’re putting too many runners on base and eventually those runs will score. WHIP is the better predictor of future performance.

OPS (On-Base Plus Slugging) is the most widely used all-in-one hitting stat because it captures both plate discipline (OBP) and power (SLG). A player with a .260 BA but a .380 OBP and .480 SLG (.860 OPS) is more valuable than a .310 BA hitter with a .340 OBP and .400 SLG (.740 OPS). MLB tracking confirms OPS correlates with run production better than any single traditional stat.

Batting average dominated baseball analysis for a century. It’s clean, simple, and every fan understands it. But it has a fundamental flaw: it treats all hits equally and ignores walks entirely.

Consider two players:

• Player A: .310 BA, .340 OBP, .400 SLG → .740 OPS
• Player B: .270 BA, .380 OBP, .480 SLG → .860 OPS

Player A has the better batting average by 40 points. But Player B reaches base more often (walks), hits for more power (extra-base hits), and creates more runs. By OPS, Player B is clearly better — and the data backs it up.

This is why front offices shifted from BA to OPS — batting average tells you part of the story. OPS tells you most of it.

At-bats include hits, outs by swinging or called strikes, fielder’s choice, and reaching on error. They do NOT include walks, hit-by-pitch, sacrifice bunts, sacrifice flies, or catcher’s interference. This distinction matters because OBP uses plate appearances (all of the above) as its denominator — that’s why a player’s OBP can be significantly higher than their BA.

The most common mistake when calculating batting average is including plate appearances that aren’t at-bats.

Counts as an At-Bat: Any hit, any out where the batter swung or was called out on strikes, fielder’s choice, reaching on an error.

Does NOT count: Walk (BB), hit by pitch (HBP), sacrifice bunt, sacrifice fly, catcher’s interference.

This is why OBP uses plate appearances (AB + BB + HBP + SF) as the denominator instead of just at-bats — it captures every time the batter came to the plate.

Baseball records partial innings in thirds — 5.1 IP means 5 innings plus 1 out (not 5.1 decimal innings). For ERA and WHIP math, convert: 5.1 = 5.333, 5.2 = 5.667. This calculator accepts complete innings and additional outs separately and converts automatically so the ERA/WHIP formulas use the correct decimal value.

When calculating ERA and WHIP, partial innings matter. Baseball records innings pitched in thirds:

• 5.0 IP = 5 complete innings (15 outs)
• 5.1 IP = 5 innings + 1 out = 5.333 in decimal
• 5.2 IP = 5 innings + 2 outs = 5.667 in decimal

Our calculator handles this automatically — enter complete innings and additional outs separately.