How to Convert BTU per Hour to Tons and Thermal kW

By Coloring Studio November 04, 2026

Cooling capacity is often stated in BTU per hour, refrigeration tons or thermal kilowatts. These units describe the rate at which heat is transferred. Converting between them helps you compare specifications written in different units, but it does not determine which air conditioner a room needs.

The BTU/h to Tons Calculator converts in all three directions. It uses 12000 BTU/h per refrigeration ton and the International Table definition of the BTU when converting to thermal kilowatts.

Convert BTU per hour to refrigeration tons

Use refrigeration tons = BTU/h / 12000. For a capacity of 24000 BTU/h, divide 24000 by 12000 to obtain 2 tons. A capacity of 18000 BTU/h is 1.5 tons, while 36000 BTU/h is 3 tons.

To convert back, multiply refrigeration tons by 12000. For example, 2.5 tons x 12000 = 30000 BTU/h. A refrigeration ton is a conventional capacity unit. It does not describe the equipment's physical weight.

Try the calculator example

Choose Input unit as BTU per hour (BTU/h). Enter Capacity value 24000, then select Convert capacity. The results show 24000 BTU/h, 2 refrigeration tons and approximately 7.033706 thermal kW.

For the reverse calculation, choose Refrigeration tons (TR), enter Capacity value 2 and convert again. Changing the unit selector reinterprets the entered number rather than converting the input field automatically, so enter a value that matches your chosen unit.

Convert BTU/h to thermal kilowatts

The International Table BTU equals 1055.05585262 joules. There are 3600 seconds in an hour and 1000 watts in one kilowatt. Therefore, thermal kW = BTU/h x 1055.05585262 / 3600000.

Using that factor, 12000 BTU/h is approximately 3.516853 thermal kW. For 24000 BTU/h, the result is approximately 7.033706 thermal kW. The calculator retains the unrounded factor internally, so calculations using a shortened factor such as 3.517 may differ slightly.

To start from kilowatts, select Thermal kilowatts (kW) and enter the capacity. One thermal kilowatt converts to approximately 3412.141633 BTU/h or 0.284345 refrigeration tons.

Distinguish BTU from BTU per hour

A BTU alone is an amount of energy. BTU per hour is energy transferred per unit time, which is power. Equipment descriptions sometimes shorten BTU/h to BTU in informal wording, but you should check that the specification describes a capacity rate before using it here.

This converter does not convert an isolated energy quantity into tons. Nor does it calculate energy used over a period. Kilowatt-hours measure energy, while kilowatts measure power; those quantities require different inputs and calculations.

Thermal capacity is not electrical input

An air conditioner moves heat using electrical energy. Its thermal cooling capacity can differ substantially from its electrical input power. A conversion showing 7.033706 thermal kW does not mean the unit draws that amount of electricity.

Electrical consumption depends on efficiency and operating conditions. Estimating electricity use also requires runtime and cycling information. This tool does not calculate COP, EER, seasonal efficiency, kWh or electricity cost from a capacity rating alone.

Use conversions without confusing them with sizing

A room's cooling load depends on climate, insulation, windows, solar exposure, ventilation, occupancy and other heat sources. Two rooms with the same floor area can have different loads. Nominal equipment capacity may also differ from delivered capacity under actual conditions.

Use a suitable load calculation and manufacturer performance data when selecting equipment. The converter does not recommend a tonnage from room area. For measuring the floor area separately, use the Square Footage Calculator.

Results display up to six decimal places. Those digits describe the conversion, not the accuracy of a manufacturer's rounded rating. Other BTU definitions may produce slightly different factors, so use consistent definitions when comparing detailed technical data.