average speed calculator enter the value and click "calculate", the calculation result will be displayed. formula: average speed(vav) = 1/2 (vi + vf) initial speed (vi) = 2 (vav) - vf speed(vf) = 2 (vav) - vi choose a calculator: --choose-- initial speed speed average speed initial speed (vi) : ms-1 speed(vf) : ms-1 average speed(vav) : ms-1 calculation result: