Ultimate Base Running (UBR) captures the pure instinctive value a player adds on the bases, stripping out stolen base attempts and double-play avoidance to focus only on advancement decisions and speed.
It turns raw movement into a single run expectancy number that lines up cleanly with WAR.
Use the simple tool below to plug in FanGraphs components and instantly discover how much your favorite player helps or hurts between the lines.
Ultimate Base Running (UBR) Calculator
Ultimate Base Running Calculator FAQ
What is Ultimate Base Running?
UBR is a run-based metric that measures how many runs a player adds or costs his team through decisions and speed on the bases, excluding steals and double-play outcomes.
How is the statistic calculated?
FanGraphs builds UBR from detailed play-by-play data, comparing a runner’s advancement on outs, singles, doubles, and other events to league averages, then translating the differences into runs.
Why does the calculator ask for BsR, wSB, and wGDP?
BsR is the umbrella base-running value.
Subtracting the stolen-base component (wSB) and the double-play component (wGDP) isolates the pure advancement portion, which is UBR.
Should I use seasonal or career numbers?
You can use either.
Seasonal numbers show performance in a single year, while career figures smooth out fluctuations and give a broader view of a player’s skills.
What is a good UBR score?
Positive UBR marks mean a player is adding runs with his base running.
Anything above +2 in a full season is typically viewed as strong; negative values indicate room for improvement.