Convert Kilocalorie to British Thermal Unit (kcal → BTU)

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

1. 1
   Take your value in kilocalories

   Start with the number of kilocalories (kcal) you want to convert.
2. 2
   Multiply by 3.965667

   The conversion factor from kcal to BTU is 3.965667. Multiply your value by this number.
3. 3
   Read the result in BTU

   The result is your value in BTU (BTU).

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

• ✓1 kcal = 4.184 kJ.
• ✓US "Calorie" (with capital C) = 1 kcal.
• ✓Apps and smartwatches track active energy in kcal.

• ✗Reading food "Calories" as gram calories — factor of 1000 off.
• ✗Treating all calorie values as comparable — macros (fat, protein, carb) differ in energy density.
• ✗Counting kcal without portion size leads to underestimates.

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.

• Nutrition labels worldwide
• Diet and weight-management tracking
• Dietetics and clinical nutrition

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