Calculate weighted on-base average with finalized 2025 MLB event coefficients, or replace the coefficient set for another season or competition.
wOBA Formula
Weighted on-base average, abbreviated wOBA, assigns a season-specific run-value weight to each major way a batter reaches base. Unlike standard OBP, it does not treat a walk, single, double, triple, and home run as equally valuable:
Here, uBB means unintentional walks. Intentional walks are removed from total walks before the numerator and denominator are calculated.
Finalized 2025 MLB Coefficients
The default mode uses the finalized 2025 FanGraphs coefficients: 0.691 for an unintentional walk, 0.722 for a hit-by-pitch, 0.882 for a single, 1.252 for a double, 1.584 for a triple, and 2.037 for a home run. The 2025 league wOBA was .313 and the wOBA scale was 1.232.
Coefficients are recalculated for each season’s run environment. The calculator therefore labels the coefficient year and provides a custom mode instead of presenting one set as timeless.
Deriving Singles and Unintentional Walks
These derivations let the calculator use values available in a standard batting line while still applying the proper event weights.
Example
Consider 200 at-bats, 50 hits, 10 doubles, 2 triples, 8 home runs, 20 walks with no intentional walks, 2 hit-by-pitches, and 3 sacrifice flies. The line contains 30 singles. Applying the 2025 weights gives a weighted numerator of 73.708 and a denominator of 225. Dividing produces approximately .328 wOBA.
Interpretation and Limits
- wOBA values offensive events by their average relationship to run scoring in the selected environment.
- The basic calculation is context neutral and does not include the score, inning, base state, park adjustment, or opponent.
- Modern FanGraphs-style wOBA does not include stolen bases or caught stealing in this batting formula.
- Custom weights should come from a single season and methodology.
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Sources
Major League Baseball. MLB Glossary: Weighted On-base Average (wOBA), current edition.
FanGraphs. Guts! wOBA and FIP Constants, finalized 2025 season.
FanGraphs Sabermetrics Library. wOBA methodology.