How many joules are in a calorie?

1 cal = 4.184 J. To convert any amount, multiply by 4.184.

How do you convert calories to joules?

Multiply the number of calories by 4.184 to get joules. The formula is shown in the "How it's calculated" section above.

Where does the conversion factor come from?

It's a published international standard. Most are defined exactly by international agreement (e.g. 1 inch = 25.4 mm exactly, 1 lb = 0.45359237 kg exactly). Source citations are listed under the formula above.

Unit converter — Energy

Calories to joules converter

Convert calories (cal) to joules (J). Source-cited conversion factor, exact to the displayed precision.

Results are mathematically exact for the displayed precision. How we calculate.

How it's calculated

Convert calories to joules— the formula

Calories convert to joules by multiplying by the published conversion factor. The factor below is exact to the precision shown, sourced from the citation under the formula.

J = cal × 4.184

cal = J × 0.239006

Joule: SI derived. 1 cal (thermochemical) = 4.184 J exactly; 1 kcal = 1000 cal. 1 kWh = 3,600,000 J exactly. 1 BTU (IT) = 1055.05585262 J (NIST SP 811).

Questions

Frequently asked questions

How many joules are in a calorie?
1 cal = 4.184 J. To convert any amount, multiply by 4.184.
How do you convert calories to joules?
Multiply the number of calories by 4.184 to get joules. The formula is shown in the "How it's calculated" section above.
Where does the conversion factor come from?
It's a published international standard. Most are defined exactly by international agreement (e.g. 1 inch = 25.4 mm exactly, 1 lb = 0.45359237 kg exactly). Source citations are listed under the formula above.