BTU to kW Converter

BTU/hr to kW conversion for HVAC and thermal capacity

If you are comparing heating or cooling equipment across spec sheets, you will often see capacity listed in BTU per hour (BTU/hr) in one place and kilowatts (kW) in another. This BTU to kW converter is built for that exact situation: you have a BTU/hr rating and need the equivalent kW quickly, without guessing or mixing up units.

BTU/hr and kW are both units of power. BTU/hr is common in US HVAC and appliance documentation, while kW is common in electrical, engineering, and international contexts. Because they measure the same kind of thing, the conversion is a straight multiplication. You do not need room size, insulation, temperature difference, or any other building details to do the unit conversion itself. Those details matter for sizing equipment, but they are a different problem.

To use the calculator, enter the capacity in BTU/hr (for example, 12,000 BTU/hr for a typical small air conditioner rating). Click Convert to see the equivalent in kW and watts. You will also see tons of refrigeration (TR) as a secondary reference because many HVAC discussions still use tons for cooling capacity comparisons. The main output is kW, since that is the most common target unit when you are comparing across engineering documents.

Assumptions and how to use this calculator

• This converts BTU/hr (power) to kW (power). It does not convert BTU (energy) to kWh (energy).
• The conversion uses the standard relationship 1 kW = 3412.141633 BTU/hr (approx).
• “Tons of refrigeration” is calculated as BTU/hr ÷ 12,000 and is included only as a reference.
• Results represent thermal power capacity. Electrical input power for HVAC equipment can be different due to efficiency (COP/EER/SEER).
• If you do not enter a rounding value, the calculator defaults to two decimal places for readability.

Common questions

Is BTU/hr the same as BTU?

No. BTU is a unit of energy. BTU/hr is energy per hour, which is power. HVAC capacity is usually given as BTU/hr. If your source lists plain BTU, it is not a capacity rating unless a time period is included.

Does this tell me how much electricity the unit uses?

No. This converts thermal capacity units only. An air conditioner with a cooling capacity of 3.5 kW does not necessarily draw 3.5 kW of electrical power. Electrical input depends on efficiency metrics like COP or EER. This page is for unit conversion, not efficiency or operating cost.

Why do I see “tons” in HVAC specs and what does it mean?

A “ton of refrigeration” is a traditional cooling capacity unit equal to 12,000 BTU/hr. It is commonly used in HVAC discussions. The calculator includes it so you can sanity-check common sizes (for example, 12,000 BTU/hr is about 1 ton).

What is the exact formula used here?

The calculator uses kW = BTU/hr ÷ 3412.141633. It also shows watts as W = kW × 1000. Those are direct unit conversions, with no additional modeling.

My spec sheet lists kBTU/hr or MBH. How do I enter that?

kBTU/hr means thousands of BTU/hr. MBH is also commonly used to mean thousand BTU/hr. Convert it to BTU/hr first by multiplying by 1,000, then enter the result. Example: 24 kBTU/hr becomes 24,000 BTU/hr.