A kilocalorie is 1,000 calories.
Kilocalories to Megajoules Converter — kcal to MJ
Convert Kilocalorie (kcal) to Megajoule (MJ) using the exact conversion factor (1 kilocalorie = 0.004184 megajoule). See the formula, worked examples, and conversion table.
Kilocalories to Megajoules converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Megajoule is 1000000 joule units.
Result = input x 4184 / 1e+6.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Kilocalories to Megajoules
Kilocalorie and Megajoule both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: A kilocalorie is 1,000 calories, and megajoule is 1000000 joule units.
Formula
megajoules = kilocalories × 0.004184
This factor comes from each unit's defined relationship to the category's base unit: 1 kilocalorie equals 4184 base units, and 1 megajoule equals 1000000 base units, so dividing one by the other gives the direct kilocalorie-to-megajoule factor of 0.004184.
Simple example
1 kcal × 0.004184 = 0.004184 MJ
1 kilocalorie = 0.004184 megajoules.
Real-world example
100 kcal × 0.004184 = 0.4184 MJ
100 kilocalories = 0.4184 megajoules.
Conversion table
| Kilocalorie (kcal) | Megajoule (MJ) |
|---|---|
| 1 kcal | 0.004184 MJ |
| 10 kcal | 0.04184 MJ |
| 50 kcal | 0.2092 MJ |
| 100 kcal | 0.4184 MJ |
| 500 kcal | 2.092 MJ |
| 1,000 kcal | 4.184 MJ |
Reverse conversion: Megajoule to Kilocalorie
0.004184 MJ × 239.0057361 = 1 kcal
0.004184 megajoules = 1 kilocalorie.
kilocalories = megajoules × 239.005736138
For a page dedicated to this direction, see Megajoule to Kilocalorie.
Understanding the Kilocalorie (kcal)
A kilocalorie is 1,000 calories.
Understanding the Megajoule (MJ)
Megajoule is 1000000 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many megajoules are in 1 kilocalorie?
1 kilocalorie equals 0.004184 megajoules, using the exact defined conversion factor rather than an estimate.
How do I convert kilocalorie to megajoule?
Multiply the kilocalorie value by 0.004184. The converter above does this instantly to whatever precision you set.
How do I convert megajoule back to kilocalorie?
Use the reverse factor: 1 megajoule equals 239.0057361 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 engineering.
What is a megajoule?
Megajoule (MJ) is a unit of engineering.
Is the kilocalorie to megajoule conversion exact?
Yes. Both kilocalorie and megajoule are defined by fixed standards rather than physical artifacts, so the factor of 0.004184 used above is exact to as many digits as you choose to display.
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.