This calculator allows you to convert from Horsepower (550 ft*lbf/s) to Milliwatt and in a reverse direction. To convert from Horsepower (550 ft*lbf/s) to Milliwatt, enter the amount of Horsepower (550 ft*lbf/s) into the first input and to convert from Milliwatt to Horsepower (550 ft*lbf/s), enter the amount of Milliwatt into the second input.