On-Base Percentage Calculator
On-Base Percentage is 0 .
On-Base Percentage Calculation Method
On-Base Percentage = (Hits + Walks + HBP) / (At-bats + Walks + HBP + Sacrifice flies)
About This Calculator
On-base percentage (OBP) measures how often a batter reaches base per plate appearance, counting hits, walks and hit-by-pitches. It is a better indicator of run-scoring value than batting average, because not making an out is what matters.
Enter hits, walks, hit-by-pitches, at-bats and sacrifice flies to calculate OBP.
A league-average OBP is around .320, and .400 is elite — reaching base in two of every five plate appearances. Because walks and hit-by-pitches count, OBP predicts run scoring far better than batting average: a .300 average with a .400 OBP is worth more to an offence than a .320 average with a .350 OBP.
Key Formula:
OBP = (H + BB + HBP) / (AB + BB + HBP + SF)Frequently Asked Questions
What is a good on-base percentage?
OBP runs about 20 points higher than batting average for a typical player. An OBP of .350 is good, .370 is very good and .400 is elite — only a handful of players sustain it.
Why is OBP more useful than batting average?
Batting average ignores walks, which are as valuable as singles for avoiding outs and setting up runs. Teams like the Oakland A's popularised OBP in the "Moneyball" era because the market undervalued it.
Does reaching base on an error count toward OBP?
No. Reaching on an error counts as a plate appearance with no hit and no walk, so it lowers OBP even though the batter ended up on base. OBP measures the ability to avoid making outs, not the ability to reach base by any means.
How many plate appearances are needed for a reliable OBP?
Around 300 plate appearances is the usual minimum, and 500 or more makes the number properly comparable across a season. Below that, random variation dominates — a .380 OBP over 100 plate appearances can easily be a .320 hitter on a hot streak.
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Sources & last update
2026-10-19