Convert British Thermal Unit to Kilocalorie (BTU → kcal)

The British thermal unit is the standard for American HVAC systems, gas appliances, and air-conditioner ratings.

British Thermal Unit

Kilocalorie

0.252164

1 BTU0.252164 kcalNIST · BIPM accuracy

British Thermal Unit to Kilocalorie Conversion Table

10 common values

British Thermal Unit	Kilocalorie
1 BTU	0.252164 kcal
10 BTU	2.521644 kcal
100 BTU	25.21644 kcal
500 BTU	126.0822 kcal
1,000 BTU	252.1644 kcal
5,000 BTU	1,260.822 kcal
10,000 BTU	2,521.644 kcal
50,000 BTU	12,608.22 kcal
100,000 BTU	25,216.44 kcal
500,000 BTU	126,082.2 kcal

How to Convert British Thermal Unit to Kilocalorie Manually

Step by Step

Converting BTU to kilocalories is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1
Take your value in BTU
Start with the number of BTU (BTU) you want to convert.
2
Multiply by 0.252164
The conversion factor from BTU to kcal is 0.252164. Multiply your value by this number.
3
Read the result in kilocalories
The result is your value in kilocalories (kcal).

Practical Examples

1 BTU

equals

0.252164 kcal

5 BTU

equals

1.260822 kcal

10 BTU

equals

2.521644 kcal

25 BTU

equals

6.30411 kcal

100 BTU

equals

25.21644 kcal

Formula

Multiply the value in BTU by 0.252164. For the reverse direction, multiply by 3.965667.

Forwardkcal = BTU × 0.252164

ReverseBTU = kcal × 3.965667

Example: 10 BTU × 0.252164 = 2.521644 kcal

Tips

Use these in everyday conversions

1 BTU = 1055.06 J = 0.293 Wh.
BTU/h (power) and BTU (energy) are different — don't confuse.
Tons of refrigeration: 12,000 BTU/h = 1 ton AC.

Common Mistakes

Avoid these

Confusing BTU and BTU/h — energy vs power.
Using kcal when BTU is requested in HVAC specs.
Treating all BTUs as exact — definitions vary (IT, thermochemical, etc.).

About British Thermal Unit and Kilocalorie

What is the British Thermal Unit?

The British thermal unit (BTU) equals approximately 1,055.06 joules and is the standard unit in American HVAC, gas appliances, and air-conditioner ratings. Originally defined as the heat needed to raise 1 pound of water by 1°F, the BTU is the imperial counterpart to the calorie. American gas utilities measure delivered heat in BTUs or therms (1 therm = 100,000 BTU), and air conditioners are rated by their cooling capacity in BTU per hour (a typical window AC is 5,000–12,000 BTU/h, central AC for a medium home is 24,000–60,000 BTU/h). Furnaces are similarly rated. The BTU relates to the joule (1 BTU ≈ 1,055 J), the calorie (1 BTU ≈ 252 cal), the watt-hour (1 BTU ≈ 0.293 Wh), and the therm (100,000 BTU = 1 therm). Outside the United States, the BTU is rare; metric countries use kilojoules or kilowatt-hours for the same applications.

US air-conditioner sizing
US heating-system capacity
Natural gas billing in some US regions

Real-world examples

Window AC: 5000–12,000 BTU/h. Central AC: 24,000–60,000 BTU/h. Home furnace: 60,000–100,000 BTU/h.

What is the Kilocalorie?

The kilocalorie equals 1,000 small calories or exactly 4.184 kilojoules and is the universal unit for measuring dietary energy in food. Confusingly, on US food labels and in popular usage, 'Calorie' (capital C) means kilocalorie — so a 200-Calorie cookie is actually 200,000 small calories, or 200 kcal. This convention dates to American chemist Wilbur Atwater's 19th-century nutrition research. Recommended daily intake is roughly 2,000 kcal for women and 2,500 kcal for men. The kilocalorie remains the everyday food-energy unit in the United States, while European labels show both kJ and kcal. Athletes track caloric burn during exercise in kcal: running burns about 100 kcal per mile. The kcal relates to the kilojoule (4.184 kJ = 1 kcal), the joule (1 kcal = 4,184 J), and the BTU (1 BTU ≈ 0.252 kcal). Marathon runners burn roughly 2,600 kcal during a 42-km race.