On-Base Percentage Calculator

Enter a batter's At-Bats (AB), Hits (H), Walks (BB), Hit by Pitch (HBP), and Sacrifice Flies (SF) to calculate their On-Base Percentage (OBP). The On-Base Percentage Calculator also computes OPS when you provide Total Bases (TB), and rates the result against MLB benchmarks so you know exactly how the batter stacks up. Also try the Passer Rating Calculator (NFL).

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

Total number of official at-bats (plate appearances excluding walks, HBP, and sacrifice flies).

Total hits including singles, doubles, triples, and home runs.

Base on balls (walks) issued to the batter.

Times the batter reached base by being hit by a pitch.

Fly balls that scored a runner; counted in the denominator but not as at-bats.

Optional — enter total bases to also calculate OPS (OBP + Slugging Percentage).

Results

On-Base Percentage (OBP)

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Performance Rating

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Times On Base

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Plate Appearances (denominator)

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Slugging Percentage (SLG)

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OPS (OBP + SLG)

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Results Table

Frequently Asked Questions

What is On-Base Percentage (OBP)?

On-Base Percentage (OBP) measures how frequently a batter reaches base per plate appearance. It counts hits, walks, and times hit by a pitch, making it a more complete picture of offensive value than batting average alone. Despite the name, OBP is technically an average (expressed as a decimal like .360), not a true percentage. See also our calculate GAA (Goals Against Average).

How do you calculate On-Base Percentage?

The formula is: OBP = (H + BB + HBP) / (AB + BB + HBP + SF). Add together the batter's Hits, Walks, and Hit by Pitches, then divide by the sum of At-Bats, Walks, Hit by Pitches, and Sacrifice Flies. Reaching base on an error or fielder's choice does NOT count toward OBP.

What is a good OBP in baseball?

As a general MLB benchmark: below .300 is considered poor, .310–.339 is below average, .340–.369 is average to solid, .370–.399 is great, and .400 or above is elite. The all-time single-season record is .609, set by Barry Bonds in 2004.

Why is OBP more valuable than batting average?

Batting average only counts hits, ignoring walks and hit-by-pitches — all of which result in the batter reaching base safely. Since outs are precious in baseball, OBP captures a batter's full ability to avoid making outs, making it a superior indicator of offensive contribution. You might also find our Game Score Calculator (Basketball) useful.

What is OPS and how does it relate to OBP?

OPS stands for On-Base Plus Slugging and is calculated as OBP + Slugging Percentage (Total Bases / At-Bats). It combines a batter's ability to get on base with their power to hit for extra bases. An OPS above .800 is considered good at the MLB level, while .900+ is excellent.

Do sacrifice flies hurt a player's OBP?

Yes, sacrifice flies are included in the denominator of the OBP formula but do not count as times on base in the numerator. This means more sacrifice flies will slightly lower a batter's OBP, even though they represent productive plate appearances that scored runs.

Does reaching base on an error count toward OBP?

No. Reaching base via a fielding error or fielder's choice is not credited to the batter's OBP. Only hits, walks (BB), and hit-by-pitches (HBP) are counted as times on base for OBP purposes.

What is the MLB record for on-base percentage in a single season?

Barry Bonds holds the MLB record with an OBP of .609 in 2004. That season he had 373 at-bats, 135 hits, 232 walks, 9 hit by pitches, and 3 sacrifice flies — an almost unprecedented demonstration of on-base ability.