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BTU to kW Converter

Convert a cooling or heating load between BTU per hour, kilowatts and tons of refrigeration. Type any one value and the calculator returns the other two using the exact conversions 1 kW = 3412.142 BTU/h and 1 ton = 12000 BTU/h.

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How to use this calculator

Enter Values

Enter your values and press Calculate to see results.

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Enter your figure in the one box you know — BTU/h, kW, or tons of refrigeration.
  2. Leave the other two boxes blank; the tool solves them and highlights the results.
  3. Read off the equivalent values, and open the steps to see each conversion factor applied.

How it works

All three units express the same rate of heat flow. The tool first converts your single input to BTU/h (kW × 3412.142, or tons × 12000), then divides that BTU/h figure by 3412.142 to get kilowatts and by 12000 to get tons of refrigeration. The factors are exact by definition, so the round-trip is loss-free.

Worked example

Worked example. A split system is rated 12,000 BTU/h. Dividing by 3412.142 gives 3.517 kW, and dividing by 12000 gives exactly 1 ton of refrigeration — the classic 12,000 BTU = 1 ton relationship.

Common mistakes

  • Entering more than one value — the tool needs exactly one so it knows what to solve.
  • Confusing BTU/h (a power/rate) with BTU (a quantity of energy); air-conditioner ratings are always BTU per hour.
  • Treating a ton of refrigeration as a weight — it is a rate of cooling, not a mass.

Frequently asked questions

Why is 1 ton equal to 12,000 BTU/h?

A ton of refrigeration was defined as the cooling rate that melts one short ton (2000 lb) of ice over 24 hours, which works out to almost exactly 12,000 BTU per hour.

Does this size an air conditioner for my room?

No. It only converts between units. Correctly sizing a unit also depends on room area, ceiling height, insulation, windows, occupancy and climate — use a dedicated sizing tool for that.

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Tip: Enter any known values to calculate the remaining results.

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