What this calculator does
On-base percentage (OBP) works out how often a batter reaches base safely per plate appearance, baseball or softball. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaOBP = (hits + walks + hit-by-pitch) ÷ (at-bats + walks + hit-by-pitch + sacrifice flies)
The inputs explained
| Field | What to enter |
|---|---|
| Hits | A number. Starts at 150. |
| Walks (BB) | A number. Starts at 60. |
| Hit by pitch (HBP) | A number. Starts at 5. |
| At-bats | A number. Starts at 500. |
| Sacrifice flies (SF) | A number. Starts at 5. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with hits
Every other input is held at the calculator’s starting values while hits varies. Select any row to load that scenario into the calculator.