Divide the amount of Btus per hour by 1,000 to calculate the amount of MBH. For example, the amount of Btus per hour is 20,000. Dividing that by 1,000 would result in 20 MBH.
Multiply the amount of watts by 0.293 to calculate the amount of MBH. For example, the number of watts is 250,000. Multiplying that amount by 0.293 results in 73,250 MBH.
Multiply the amount of horsepower by 2.544 to calculate the amount of MBH. For example, if the amount of horsepower is 10,000, then multiplying it by 2.544 will result in 25,440 MBH.