Navigation: Realtest Script Language > Syntax Element Details > OBV Category Indicator Functions Description On Balance Volume indicator Syntax OBV(len) Parameters len - lookback period Notes Traditional OBV is simply the sum of up-bar volume minus the sum of down-bar volume for the specified period. RealTest divides this value by the sum of all volume for the specified period to express it as a percentage. This indicator could be written as (Sum((C > C[1]) * V, len) - Sum((C < C[1]) * V, len)) / Sum(V, len). Copyright © 2020-2025 Systematic Solutions, LLC