A kilocalorie is 1,000 calories.
Kilocalories to Millijoules Converter — kcal to mJ
Convert Kilocalorie (kcal) to Millijoule (mJ) using the exact conversion factor (1 kilocalorie = 4,184,000 millijoule). See the formula, worked examples, and conversion table.
Kilocalories to Millijoules converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
Millijoule is 0.001 joule units.
Result = input x 4184 / 0.001.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Kilocalories to Millijoules
Kilocalorie and Millijoule both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Specifically: A kilocalorie is 1,000 calories, and millijoule is 0.001 joule units.
Formula
millijoules = kilocalories × 4184000
This factor comes from each unit's defined relationship to the category's base unit: 1 kilocalorie equals 4184 base units, and 1 millijoule equals 0.001 base units, so dividing one by the other gives the direct kilocalorie-to-millijoule factor of 4184000.
Simple example
1 kcal × 4184000 = 4,184,000 mJ
1 kilocalorie = 4,184,000 millijoules.
Real-world example
100 kcal × 4184000 = 418,400,000 mJ
100 kilocalories = 418,400,000 millijoules.
Conversion table
| Kilocalorie (kcal) | Millijoule (mJ) |
|---|---|
| 1 kcal | 4,184,000 mJ |
| 10 kcal | 41,840,000 mJ |
| 100 kcal | 418,400,000 mJ |
| 500 kcal | 2,092,000,000 mJ |
| 1,000 kcal | 4,184,000,000 mJ |
| 2,000 kcal | 8,368,000,000 mJ |
Reverse conversion: Millijoule to Kilocalorie
1 mJ × 2.390057e-7 = 2.390057e-7 kcal
1 millijoule = 2.390057e-7 kilocalories.
kilocalories = millijoules × 2.390057e-7
For a page dedicated to this direction, see Millijoule to Kilocalorie.
Understanding the Kilocalorie (kcal)
A kilocalorie is 1,000 calories.
Understanding the Millijoule (mJ)
Millijoule is 0.001 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millijoules are in 1 kilocalorie?
1 kilocalorie equals 4,184,000 millijoules, using the exact defined conversion factor rather than an estimate.
How do I convert kilocalorie to millijoule?
Multiply the kilocalorie value by 4184000. The converter above does this instantly to whatever precision you set.
How do I convert millijoule back to kilocalorie?
Use the reverse factor: 1 millijoule equals 2.390057e-7 kilocalories. You can also use the swap control in the converter above to flip the direction instantly.
What is a kilocalorie?
Kilocalorie (kcal) is a unit of energy.
What is a millijoule?
Millijoule (mJ) is a unit of energy.
Is the kilocalorie to millijoule conversion exact?
Yes. Both kilocalorie and millijoule are defined by fixed standards rather than physical artifacts, so the factor of 4184000 used above is exact to as many digits as you choose to display.