Convert mechanical, electric, metric, or boiler horsepower to BTU per hour and back, with watts, kilowatts, refrigeration tons, and energy over time.

Btu uses the International Table (IT) definition. This converts power; equipment efficiency is not inferred.

Optional settings

Blank omits energy. Zero reports zero energy.

Related Calculators

hp to BTU/hr Formula

The following formula is used to convert horsepower to BTU per hour.

BtuIT / hr ≈ mechanical hp × 2544.433578

Variables:

  • BtuIT/hr is power: the rate of energy transfer in International Table British thermal units per hour
  • Hp is the horsepower
  • Approximately 2544.433578 BtuIT/hr per mechanical horsepower is the conversion factor; other horsepower definitions use different factors

For mechanical horsepower, multiply by approximately 2544.433578 to obtain BtuIT/hr. The calculator normalizes the selected horsepower definition to watts, then converts to BtuIT/h or BtuIT/min. BtuIT/min = BtuIT/hr ÷ 60. Optional elapsed hours multiply power to obtain energy in kWh and BtuIT; blank omits energy.

Mechanical Horsepower to BtuIT per Hour (1 hp ≈ 2544.433578 BtuIT/hr)
Horsepower (hp) BTU per hour (BTU/hr)
⅛318.054
¼636.108
⅓848.145
½1272.217
¾1908.325
12544.434
1½3816.650
25088.867
37633.301
512722.168
7½19083.252
1025444.336
1538166.504
2050888.672
2563610.839
3076333.007
40101777.343
50127221.679
60152666.015
75190832.518
*Mechanical horsepower: 1 hp ≈ 2544.433578 BtuIT/hr. For reference, 1 kW ≈ 3412.142 BTU/hr and 1 hp ≈ 0.7457 kW.

What is Horsepower?

Horsepower (hp) is a unit of measurement for power, representing the rate at which work is done. It is commonly used to measure the power output of engines and motors. Mechanical horsepower is approximately 745.699872 W; electric horsepower is 746 W, metric horsepower is 735.49875 W and boiler horsepower uses the NIST factor 9.8095 kW. Select the matching definition; they are not interchangeable.

How to Calculate BTU/hr from Horsepower?

The following steps outline how to calculate BTU/hr from horsepower.

  1. First, determine horsepower and select its mechanical, electric, metric or boiler definition. The following example uses mechanical horsepower.
  2. Next, use the formula BtuIT/hr ≈ mechanical hp × 2544.433578 to calculate the BTU per hour.
  3. Finally, insert the values and calculate the result using the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Horsepower (Hp) = 10

BtuIT per hour ≈ 25444.336