How to convert calories to british thermal units
To convert a measurement in calories to british thermal units, multiply the value by 0.003965666831. The conversion factor comes from the relationship between both units and the joule.
For example, to convert 5 cal to british thermal units: 5 × 0.003965666831 = 0.019828334157 BTU.
What is a calorie?
A calorie (small calorie) is the energy needed to raise the temperature of one gram of water by one degree Celsius, defined as exactly 4.184 joules. The calorie originated in early-19th-century thermodynamics. The thermochemical calorie, fixed at exactly 4.184 J, is the modern standard, though it is often confused with the larger food Calorie (kilocalorie).
Common uses of calories include: Chemistry and thermodynamics; Heat-of-reaction measurements; Physics heat-transfer problems; Historical energy references.
What is a british thermal unit?
A British thermal unit (BTU) is the energy needed to raise the temperature of one pound of water by one degree Fahrenheit, about 1,055 joules. The BTU arose from imperial heating and steam engineering. It remains the dominant unit for heating, ventilation, and air-conditioning capacity in the United States, where furnaces and air conditioners are rated in BTU.
Common uses of british thermal units include: Air conditioner and furnace ratings; Heating and cooling load calculations; Natural gas and fuel energy content; HVAC system sizing in the US.
Calories to british thermal units worked examples
Here are some common values converted:
1 cal = 0.003965666831 BTU 5 cal = 0.019828334157 BTU 10 cal = 0.039656668314 BTU 50 cal = 0.19828334157 BTU 100 cal = 0.396566683139 BTU
Frequently asked questions
How many british thermal units are in one calorie?
One calorie (cal) equals 0.003965666831 british thermal units (BTU). Multiply any value in calories by 0.003965666831 to convert to british thermal units.
How do I convert calories to british thermal units?
Multiply the value in calories by 0.003965666831. For example, 5 cal × 0.003965666831 = 0.019828334157 BTU.
How do I convert british thermal units to calories?
Multiply the value in british thermal units by 252.164401, or divide by 0.003965666831. Use the swap button on the converter above to reverse the direction.
Is the calorie to british thermal unit conversion exact?
The thermochemical calorie is defined as exactly 4.184 J and the BTU as 1055.056 J. Conversions between SI energy units are exact.
What is the formula for calories to british thermal units?
The formula is: BTU = cal × 0.003965666831. This comes from the definition of both units relative to the joule.