# On-Base Percentage Calculator (OBP)

URL: https://speedycalculator.com/calculators/sports/on-base-percentage/
Last updated: 2026-10-30

> The on-base percentage calculator finds how often a batter reaches base by hit, walk or hit-by-pitch, from hits, walks, HBP, at-bats and sacrifice flies.

## Inputs

- Hits
- Walks (bases on balls)
- Hit by pitch
- At-bats
- Sacrifice flies

## Results

- On-base percentage
- Plate appearances counted

## Formula

```
OBP = (H + BB + HBP) ÷ (AB + BB + HBP + SF)
```

## Explanation

On-base percentage became famous through "Moneyball": a batter who avoids outs helps the team score, however he gets on base. An OBP above .360 is very good.

### How to use the On-Base Percentage Calculator

- **Hits**
- **Walks (bases on balls)**
- **Hit by pitch**
- **At-bats**
- **Sacrifice flies**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the batter's hits, walks, hit-by-pitches, at-bats and sacrifice flies.

### Inputs explained

FieldWhat to enterHitsA numberWalks (bases on balls)A numberHit by pitchA numberAt-batsA numberSacrifice fliesA number

### What each result means

- **On-base percentage** = ([Hits] + [Walks (bases on balls)] + [Hit by pitch])÷([At-bats] + [Walks (bases on balls)] + [Hit by pitch] + [Sacrifice flies])
- **Plate appearances counted** = [At-bats] + [Walks (bases on balls)] + [Hit by pitch] + [Sacrifice flies]

### Example values

How the main result changes when **Hits** changes and everything else stays at the example values above:

HitsOn-base percentage750.25112.50.3131500.376187.50.4382250.5013000.626

## Worked example

Inputs — Hits: 150; Walks (bases on balls): 70; Hit by pitch: 5; At-bats: 520; Sacrifice flies: 4.

Results — **On-base percentage = 0.376**; Plate appearances counted = 599.

## Key terms

- **Sacrifice fly**: A fly-ball out that scores a runner.

## FAQ

**What is a good OBP?**
Above .360 is very good; around .320 is average.

**Why are sacrifice flies included?**
They are plate appearances that produce outs.

**Do errors count?**
Reaching on an error counts as an out for OBP.

**How is OBP different from batting average?**
It also credits walks and hit-by-pitches.


## Sources

- [MLB – Glossary of statistics](https://www.mlb.com/glossary)
- [FanGraphs Sabermetrics Library](https://library.fangraphs.com/)