A kilocalorie is 1,000 calories.
Kilocalories to Petajoules Converter — kcal to PJ
Convert Kilocalorie (kcal) to Petajoule (PJ) using the exact conversion factor (1 kilocalorie = 4.184e-12 petajoule). See the formula, worked examples, and conversion table.
Kilocalories to Petajoules converter
Converter
Energy Converter
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Context values
Some unit families need one extra value for a physically accurate result.
Petajoule is 1000000000000000 joule units.
Result = input x 4184 / 1e+15.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Kilocalories to Petajoules
Kilocalorie and Petajoule 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 petajoule is 1000000000000000 joule units.
Formula
petajoules = kilocalories × 4.184e-12
This factor comes from each unit's defined relationship to the category's base unit: 1 kilocalorie equals 4184 base units, and 1 petajoule equals 1e+15 base units, so dividing one by the other gives the direct kilocalorie-to-petajoule factor of 4.184e-12.
Simple example
1 kcal × 4.184e-12 = 4.184e-12 PJ
1 kilocalorie = 4.184e-12 petajoules.
Real-world example
100 kcal × 4.184e-12 = 4.184e-10 PJ
100 kilocalories = 4.184e-10 petajoules.
Conversion table
| Kilocalorie (kcal) | Petajoule (PJ) |
|---|---|
| 1 kcal | 4.184e-12 PJ |
| 10 kcal | 4.184e-11 PJ |
| 100 kcal | 4.184e-10 PJ |
| 500 kcal | 2.092e-9 PJ |
| 1,000 kcal | 4.184e-9 PJ |
| 2,000 kcal | 8.368e-9 PJ |
Reverse conversion: Petajoule to Kilocalorie
4.184e-12 PJ × 239005736100 = 1 kcal
4.184e-12 petajoules = 1 kilocalorie.
kilocalories = petajoules × 239005736138
For a page dedicated to this direction, see Petajoule to Kilocalorie.
Understanding the Kilocalorie (kcal)
A kilocalorie is 1,000 calories.
Understanding the Petajoule (PJ)
Petajoule is 1000000000000000 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many petajoules are in 1 kilocalorie?
1 kilocalorie equals 4.184e-12 petajoules, using the exact defined conversion factor rather than an estimate.
How do I convert kilocalorie to petajoule?
Multiply the kilocalorie value by 4.184e-12. The converter above does this instantly to whatever precision you set.
How do I convert petajoule back to kilocalorie?
Use the reverse factor: 1 petajoule equals 239,005,736,100 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 petajoule?
Petajoule (PJ) is a unit of energy.
Is the kilocalorie to petajoule conversion exact?
Yes. Both kilocalorie and petajoule are defined by fixed standards rather than physical artifacts, so the factor of 4.184e-12 used above is exact to as many digits as you choose to display.