A net oil computer which can gate out turbine meter pulses by producing gating pulses of time widths T.sub.o and/or T.sub.w directly proportional to percent oil, by volume, and/or percent water, by volume, respectively, flowing as a mixture in a pipeline, where ##EQU1## K is a constant, D.sub.M IS THE MEAN DENSITY OF THE MIXTURE,d.sub.w is the water density, andd.sub.o is the oil density.A densitometer provides the d.sub.m input. The water density does not vary significantly with temperature. A temperature probe can be used to compensate for changes in d.sub.o due to changes in temperature.