# Water Horsepower

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Water Horsepower formulas

 $$\large{ WHP = \frac{ Q \; h_t }{3960} }$$ $$\large{ WHP = \eta_p \; BHP }$$

### Where:

 Units English Metric $$\large{ WHP }$$ = water horsepower $$\large{\frac{lbf-ft}{sec}}$$ $$\large{\frac{Btu}{s}}$$ $$\large{ Q }$$ = flow rate discharge $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$ $$\large{ \eta_p }$$  (Greek symbol eta) = pump efficiency $$\large{dimensionless}$$ $$\large{ h_t }$$ = total head $$\large{ft}$$ $$\large{m}$$

### Solve For:

 $$\large{ BPH = \frac{ 100 \; Q \; h_t }{ 3960 \; \eta_p } }$$ $$\large{ Q = \frac{ 3960 \; WHP }{ H } }$$ $$\large{ \eta_p = \frac{ WHP }{ BHP } }$$ $$\large{ h_t = \frac{ 3960 \; WHP }{ Q } }$$