Unlike stream water which has upstream and downstream still water does not flow from one place to another, whereas it stays stagnant, hence it can also be called as stagnant water. There will be a difference in the speed of boat which is moving in the stream water and still water. But with the help of speed of boat in still water formula in this page speed in still water and rate of a stream can be calculated on your own based on the speed in upstream and downstream.

Rate of stream (km/hr)= (1 / 2) (a - b)

Where,

a = Downstream (km/hr)

b = Upstream speed (km/hr)

On substituting the value in speed of boat in still water formula, the speeds of upstream and downstream should be substituted in the km/hr units.