LoadCairn / Cooling capacity

BTU to Tons Cooling Converter

Convert BTU/hr to refrigeration tons, or convert tons back to BTU/hr. The tool shows the arithmetic and the equivalent thermal kW using the stated factors.

Cooling capacity converter

Convert cooling capacity

Choose a direction, enter a capacity, and review the converted value with each arithmetic step shown.

Conversion direction

Cooling capacity (BTU/hr)

Starts with the requested 450,000 BTU/hr CRAC example. Changing direction clears the value so it is not reinterpreted in a different unit.

Planning estimate

Conversion result

tons: 37.5 tons
Thermal equivalent: 131.881875 kW

Calculation trace

450,000 BTU/hr ÷ 12,000 BTU/hr per ton = 37.5 tons
37.5 tons × 3.51685 kW/ton = 131.881875 kW

Planning estimate only. This result is not a substitute for a licensed engineer's design or manufacturer data.

Factors: 12,000 BTU/hr = 1 ton (ASHRAE); 1 ton = 3.51685 kW (rounded from NIST SP 811's BTU/hr-to-watt factor).

Cooling capacity / Definition

What a refrigeration ton means

A refrigeration ton is the heat required to melt one short ton of ice in 24 hours, expressed as a cooling rate. One short ton is 2,000 pounds, and spreading that heat removal across a day gives the standard rate.

12,000 BTU/hr = 1 ton

Note: 1 ton of cooling is exactly 12,000 BTU/hr. Some websites incorrectly state 22,000 BTU/hr per ton — that figure is wrong.

This page uses exactly 12,000 BTU/hr per refrigeration ton and exactly 3.51685 kW per ton for the requested kW equivalent. The kW factor is the rounded value used throughout this converter and its reference table.

Conversion factors and sources

ASHRAE Terminology, “ton of refrigeration” defines it as a cooling rate of 12,000 Btu/h and relates it to melting one 2,000 lb ton of ice.
NIST SP 811, Appendix B.8 lists 1 Btu_IT/h = 0.2930711 W. Multiplying by 12,000 gives 3.5168532 kW, rounded here to the requested 3.51685 kW per ton.

Cooling capacity / Quick reference

BTU/hr to tons quick-reference table

Each row uses tons = BTU/hr ÷ 12,000 and kW = tons × 3.51685. The values are conversions, not equipment recommendations.

6,000 BTU/hr

Tons: 0.5
kW: 1.758425

12,000 BTU/hr

Tons: 1
kW: 3.51685

18,000 BTU/hr

Tons: 1.5
kW: 5.275275

24,000 BTU/hr

Tons: 2
kW: 7.0337

30,000 BTU/hr

Tons: 2.5
kW: 8.792125

36,000 BTU/hr

Tons: 3
kW: 10.55055

42,000 BTU/hr

Tons: 3.5
kW: 12.308975

48,000 BTU/hr

Tons: 4
kW: 14.0674

60,000 BTU/hr

Tons: 5
kW: 17.58425

90,000 BTU/hr

Tons: 7.5
kW: 26.376375

120,000 BTU/hr

Tons: 10
kW: 35.1685

180,000 BTU/hr

Tons: 15
kW: 52.75275

240,000 BTU/hr

Tons: 20
kW: 70.337

360,000 BTU/hr

Tons: 30
kW: 105.5055

600,000 BTU/hr

Tons: 50
kW: 175.8425

1,200,000 BTU/hr

Tons: 100
kW: 351.685

BTU per hour, refrigeration tons, and thermal kilowatts using 3.51685 kW per ton
BTU/hr	Tons	kW
6,000	0.5	1.758425
12,000	1	3.51685
18,000	1.5	5.275275
24,000	2	7.0337
30,000	2.5	8.792125
36,000	3	10.55055
42,000	3.5	12.308975
48,000	4	14.0674
60,000	5	17.58425
90,000	7.5	26.376375
120,000	10	35.1685
180,000	15	52.75275
240,000	20	70.337
360,000	30	105.5055
600,000	50	175.8425
1,200,000	100	351.685

Cooling capacity / Worked examples

Apply the conversion

CRAC nameplate: 450,000 BTU/hr

Convert the stated nameplate cooling capacity to tons, then to its thermal kW equivalent.

450,000 BTU/hr ÷ 12,000 BTU/hr per ton = 37.5 tons
37.5 tons × 3.51685 kW/ton = 131.881875 kW

Result: 37.5 tons (131.881875 kW thermal equivalent).

Cooling requirement: 25 tons

Convert the cooling requirement back to BTU/hr and show the same capacity in kW.

25 tons × 12,000 BTU/hr per ton = 300,000 BTU/hr
25 tons × 3.51685 kW/ton = 87.92125 kW

Result: 300,000 BTU/hr (87.92125 kW thermal equivalent).

Planning estimates only. These conversions are not a substitute for a licensed engineer's design or manufacturer data; use the rated capacity and conditions provided for the actual equipment.

Questions / Cooling capacity

BTU and cooling ton questions

How many BTU is 1 ton of cooling?

One refrigeration ton is a cooling rate of 12,000 BTU/hr. It describes heat removed per hour, not a quantity of stored heat. The same capacity is 3.51685 kW using this page’s stated conversion factor.

How do I convert BTU to tons?

For a cooling rate in BTU/hr, divide by 12,000: tons = BTU/hr ÷ 12,000. For example, 450,000 BTU/hr ÷ 12,000 = 37.5 tons.

Why is a ton 12,000 BTU?

The refrigeration ton comes from the approximate heat needed to melt one short ton (2,000 lb) of ice over 24 hours. Dividing that day’s heat removal by 24 hours gives a cooling rate of 12,000 BTU/hr.

Is a ton of cooling the same as a ton of weight?

No. A ton of cooling is a rate of heat removal, measured here in BTU/hr. A short ton of weight is a mass of 2,000 lb; the refrigeration unit’s name comes from the historical ice-melting comparison.

How many tons is a typical CRAC unit?

There is no single typical capacity for every CRAC unit. Read the unit’s cooling-capacity nameplate or manufacturer data, then divide its BTU/hr rating by 12,000 to convert that rated capacity to refrigeration tons.

Does the conversion change for heating?

No. The BTU/hr-to-ton arithmetic is a heat-flow conversion and does not change direction for a heating rate. This converter does not select heating equipment or account for system efficiency, operating conditions, or manufacturer ratings.

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