On-Base Percentage Calculator
Find a hitter's on-base percentage (OBP).
Results update as you type.
How it works
On-base percentage, or OBP, measures how often a baseball hitter reaches base, and this calculator computes it from the relevant offensive stats. You enter hits, walks, times hit by a pitch, at-bats, and sacrifice flies, and it returns the on-base percentage. OBP is considered one of the most important hitting statistics because it captures a batter's fundamental job: avoiding outs and reaching base by any means, not just getting hits. The numerator adds hits, walks, and hit-by-pitches, all the ways a batter reaches base under this measure, while the denominator counts every plate appearance that puts that skill to the test: at-bats plus walks plus hit-by-pitches plus sacrifice flies. Unlike batting average, OBP credits a hitter for drawing walks, which is why a patient batter with a modest average can still have a high OBP and be very valuable. A league-average OBP is typically around .320, .350 is good, and above .400 is excellent, reached only by the most disciplined and productive hitters. OBP is the first component of OPS and a cornerstone of modern baseball analysis, since reaching base leads directly to scoring runs. Enter the hitter's hits, walks, hit-by-pitch, at-bats, and sacrifice flies to compute on-base percentage.
OBP = (H + BB + HBP) / (AB + BB + HBP + SF)
On-base percentage divides the times a batter reaches base by hits, walks, and being hit by a pitch by their total plate appearances that count, which are at-bats plus walks plus hit-by-pitch plus sacrifice flies. It measures how often a hitter avoids making an out, a broader and more valuable skill than batting average alone.
Source:Baseball statistics
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter hits, walks (bb), hit by pitch, at-bats and sacrifice flies.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
On-base percentage updates instantly as you type — no button to press.
Frequently asked questions
What is on-base percentage?
On-base percentage, or OBP, measures how often a batter reaches base via a hit, walk, or hit-by-pitch, relative to their plate appearances. It reflects a hitter's core value: avoiding outs. Because it includes walks, OBP is a broader and often more meaningful measure of offensive contribution than batting average alone.
How is OBP calculated?
Add hits, walks, and hit-by-pitches for the numerator, and divide by at-bats plus walks plus hit-by-pitches plus sacrifice flies for the denominator. For 75 times on base in 210 qualifying plate appearances, the OBP is .357. The calculator handles this formula from your five inputs to give an exact figure.
Why is OBP considered better than batting average?
Batting average ignores walks, but a walk puts a runner on base just like a single in terms of avoiding an out. OBP credits walks and hit-by-pitches, rewarding plate discipline. Since reaching base is what leads to runs, OBP correlates better with scoring than batting average, which is why analysts value it highly.
What is a good on-base percentage?
A league-average OBP is around .320, a good OBP is about .350, and an OBP above .400 is excellent, achieved only by the most disciplined, productive hitters. Elite on-base seasons can approach or exceed .450. As with other stats, compare to the league average of the season for proper context.
Why are sacrifice flies in the denominator but not sacrifice bunts?
Sacrifice flies are included in the OBP denominator because they represent a plate appearance where the batter made an out without reaching base, so they count against on-base skill. Sacrifice bunts are excluded by convention, treated as a strategic team play rather than a reflection of the individual hitter's on-base ability.