OBP Calculator
Calculate on-base percentage (OBP) — how often a hitter reaches base per plate appearance.
Informational only — not a substitute for official league statistics or professional judgment.
How it's calculated
Assumptions
- Uses the official MLB definition: sacrifice flies count in the denominator, sacrifice bunts and catcher's interference do not.
- Times reached on error or fielder's choice are not counted as reaching base — they're outs for OBP purposes, already reflected in the at-bat total.
Source: MLB Glossary — On-Base Percentage (OBP)
Last reviewed: July 2026
Frequently asked questions
What's considered a good OBP?
In recent MLB seasons league-average OBP has sat around .310–.320. An OBP of .360 or better is very good, .380+ is excellent, and a .400 OBP over a full season is elite, typically achieved by only a handful of hitters.
Why do sacrifice flies count against OBP but sacrifice bunts don't?
The official rule treats a sacrifice fly as a genuine attempt to hit that happened to produce an out, so it counts as an opportunity in the denominator. A sacrifice bunt is treated as a deliberate, manager-directed out, so it's excluded from the OBP denominator entirely.
How is OBP different from batting average?
Batting average only counts hits per at bat, ignoring walks and hit-by-pitches. OBP credits every time the batter reaches base — hits, walks, and HBP — against nearly all plate appearances, which is why it's considered the better measure of a hitter's ability to avoid outs.
How does OBP relate to OPS?
OPS is simply OBP plus slugging percentage (SLG). OBP measures how often a hitter reaches base; SLG measures how much power they hit for; OPS adds the two into one quick summary number.
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