How to Calculate Power for Hydraulic Pumps

08/20/25

“How do we calculate power for hydraulic pumps?”

Hydraulic pumps are a pillar of modern water infrastructure. Through their mechanisms, they can create a pressure differential to match the needs of people. But pumps need power to operate, and we may need to calculate the power to accomplish what our goals. To do this, we can go to the simple physics equation (1) work = force * distance (W = F * h). Going further, we may notice that if we’re lifting a fluid, the force will be equal to (2) the fluid’s mass * gravity (m_fluid * g), and (3) mass of fluid = density of fluid * volume of fluid (m_fluid = rho_fluid * V_fluid).  This is related to power through the equation (4) P = dW/dt, where Power is P. We can plug in equation (1) to (4) to make (5) P = d(F * h)/dt. → dF/dt*ht. If we substitute in equation (3), we get (6)  P =  (d(rho_fluid * V_fluid*g)/dt*h), and by (7) fluid flow = change in fluid over time (Q = dV_fluid/dt), we can substitute for (8) P = rho_fluid * g * h * dV_fluid/dt → P = rho_fluid * g * h * Q. And by remembering that (9) specific weight = density of fluid * gravity (Gamma_fluid = rho_fluid * g), we can finalize with (10) P = Gamma_fluid * Q * h. This is How to Calculate Power for Hydraulic Pumps. The pump’s efficiency will also affect this value.

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