This calculator allows you to convert from Horsepower (boiler) to Femtojoule/second and in a reverse direction. To convert from Horsepower (boiler) to Femtojoule/second, enter the amount of Horsepower (boiler) into the first input and to convert from Femtojoule/second to Horsepower (boiler), enter the amount of Femtojoule/second into the second input.