Find a hitter’s on-base percentage (OBP) — how often they reach base by any means, not just hits.
How it works
OBP is (hits + walks + hit-by-pitch) divided by (at-bats + walks + hit-by-pitch + sacrifice flies): OBP = (H + BB + HBP) ÷ (AB + BB + HBP + SF). Unlike batting average, OBP credits a hitter for drawing a walk, not just for getting a hit.
What this does not include
OBP does not weight extra-base hits — a double and a single count the same toward reaching base. Pair it with slugging percentage for a fuller offensive picture.
How to use this calculator
- Enter hits, walks, and hit-by-pitches (hit-by-pitch is optional if you don’t track it).
- Enter at-bats and sacrifice flies (also optional).
- Read off the on-base percentage.
A worked example
150 hits, 50 walks, 5 hit-by-pitch, 500 at-bats, 5 sacrifice flies: OBP = (150+50+5) ÷ (500+50+5+5) = 0.3661.
45 hits, 10 walks, 0 HBP, 180 at-bats, 2 sac flies: OBP = 0.2865.
What the variables mean
| Variable | Meaning |
|---|---|
| Hits, walks, HBP | Ways a batter safely reaches base |
| At-bats | Official at-bats |
| Sac flies | Sacrifice flies, counted in the denominator but not as a way of reaching base |
Edge cases worth knowing
OBP counts walks and hit-by-pitches, unlike batting average, which only counts hits. A patient hitter who draws many walks can have a much higher OBP than their batting average alone would suggest.
Missing hits makes the calculation impossible, so the calculator declines to show a result without it.
Why does OBP use a different denominator than batting average?
Batting average’s denominator (at-bats) excludes walks and sacrifice flies by rule, but OBP needs those plate appearances counted since it’s measuring how often a batter reaches base at all, including via a walk.
What’s a good on-base percentage?
In modern professional baseball, .360 or higher is generally considered strong, and league average tends to sit in the low .300s.
Does OBP count reaching base on an error?
No — reaching base on a fielding error isn’t counted as an official time on base for OBP purposes under standard scoring rules.
