FORMULA
How to convert
kJ = kcal × 4.184Example: 10 kcal = 41.84 kJ.
KCAL → KJ
Kilocalories to Kilojoules
Convert kilocalories to kilojoules with an exact, deterministic calculation.
LIVE CONVERSIONDECIMAL ENGINE EXACT_
1 kcal = 4.184 kJ
MULTI-CONVERT
QUICK ANSWER
1 Kilocalorie
4.184 kJ
REFERENCE TABLE
Kilocalorie to Kilojoule
| kilocalories | kilojoules |
|---|---|
| 1 kcal | 4.184 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 25 kcal | 104.6 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
ABOUT THIS CONVERSION
Convert kilocalories to kilojoules
This page converts kilocalories (kcal) to kilojoules (kJ). Convertor4U first interprets the input using Kilocalorie's definition, then expresses the same quantity in Kilojoule. The result is calculated from the stored factor and offset definitions, not from a rounded lookup table.
Real-world example
For comparing an electricity bill, battery capacity, food energy, or heating requirement, an input of 1 kcal converts to 4.184 kJ. Keep extra digits while calculating, then round only the final value to the precision the task actually needs.
Rounding and precision
Billing and nutrition should follow the precision of the original label. Scientific work should preserve significant figures. Small electronvolt values converted to joules may be clearer in scientific notation.
Regional context
Food labels may write 'Calories' with a capital C to mean kilocalories. Kilojoules are prominent on labels in many countries, while food Calories are common in the United States. BTU conventions can vary slightly; this site states its stored factor.
Common mistake
Power and energy are different: kilowatts measure a rate, while kilowatt-hours measure an amount of energy.
Editorial method
Definitions and sources are listed below. Calculations retain more precision than the default display and round only for presentation.
USEFUL ANSWERS
kcal to kJ FAQs
How do I convert kilocalories to kilojoules?
Enter the kcal value in the calculator. It applies the stored factor and offset definitions and returns the equivalent in kJ; the formula and common-value table are shown on this page.
Is the kcal to kJ conversion exact?
Defined measurement relationships are calculated with decimal arithmetic from stored standards. The displayed answer may be rounded for readability. Currency results instead depend on the dated reference rate shown.
How many decimal places should I keep?
Billing and nutrition should follow the precision of the original label. Scientific work should preserve significant figures. Small electronvolt values converted to joules may be clearer in scientific notation.
What should I check before using the result?
Power and energy are different: kilowatts measure a rate, while kilowatt-hours measure an amount of energy.
FROM UNIT
Kilocalorie
One kilocalorie (kcal) equals 4184 joule units (J) in the converter's reference scale. It measures energy, work, or heat rather than the rate of energy transfer.
NIST Guide to the SI, SP 811 ↗Definition verified 14 August 2026TO UNIT
Kilojoule
One kilojoule (kJ) equals 1000 joule units (J) in the converter's reference scale. It measures energy, work, or heat rather than the rate of energy transfer.
NIST Guide to the SI, SP 811 ↗Definition verified 14 August 2026Content reviewed by Convertor4U Editorial Team · 16 August 2026 · Report an error on this page