DISCLAIMER:I have checked this caculator, however use it at your own risk!

For farm tractors with a 540 RPM PTO
100 ft.lbs of torque produces 10.3 HP or about 10 HP per 100 ft.lbs

INPUT two known values to calculate the third unknow!

Torque in foot lbs ft lbs

Revolutions per minute RPM

Power in horse power HP