Kilocalories to kJ Converter
Quick answer: To convert kilocalories to kJ, multiply by 4.184. For example, 10 kcal is 41.84 kJ. One kilocalorie equals 4.184 kJ.
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Use the Kilocalories to kJ Converter
Kilocalories to kJ formula and what each symbol means
kJ = kcal × 4.184
| Symbol | Meaning |
|---|---|
| kcal | Kilocalorie |
| kJ | Kilojoule |
Kilocalories to kJ examples
1 kcal
1 kcal × 4.184 = 4.184 kJ.
10 kcal
10 kcal × 4.184 = 41.84 kJ.
100 kcal
100 kcal × 4.184 = 418.4 kJ.
Kilocalories compared with kJ
One kcal is 4.184 times as large as one kJ, so your number gets bigger when you convert kilocalories to kJ and smaller when you convert back. If the answer is not larger than what you typed, you divided instead of multiplying.
About kilocalories and kJ
Kilocalorie (kcal): The thermochemical kilocalorie, exactly 4,184 joules, used for food energy. Kilojoule (kJ): 1,000 joules.
Where kilocalories to kJ conversions are used
Gas and heating are often billed in therms, BTU or megajoules. Engineering and physics calculations usually work in joules.
How to calculate Kilocalories to kJ step by step
- Enter the value in kcal (the starting unit).
- Multiply by 4.184, because 1 kcal = 4.184 kJ.
- The product is the value in kJ. To go back, divide by 4.184 or multiply by 0.2390057.
Popular energy conversions
How to read your Kilocalories to kJ result
Quick estimate: multiply by about 4.2 to get kJ from kilocalories; this is within 0.4% of the exact factor. Food labels use the kilocalorie (kcal, written Calorie in the US), electricity bills use the kilowatt hour, and heating uses the Btu.
| KILOCALORIES | KJ |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 5 | 20.92 |
| 10 | 41.84 |
| 20 | 83.68 |
| 50 | 209.2 |
| 100 | 418.4 |
| 1,000 | 4,184 |
kJ to Kilocalories: quick table
| KJ | KILOCALORIES |
|---|---|
| 1 | 0.2390057 |
| 5 | 1.195029 |
| 10 | 2.390057 |
| 25 | 5.975143 |
| 50 | 11.95029 |
| 100 | 23.90057 |
| 250 | 59.75143 |
| 500 | 119.5029 |
Common mistakes when calculating Kilocalories to kJ
- Confusing kW (power) with kWh (energy).
- Dividing when you should multiply: from kcal to kJ multiply by 4.184; from kJ to kcal divide by 4.184.
Kilocalories to kJ FAQ
How many kJ are in 1 kcal?
1 kcal equals 4.184 kJ.
How many kcal are in 1 kJ?
1 kJ equals 0.2390057 kcal.
Is 1 kcal = 4.184 kJ an exact conversion?
Yes. The kilocalorie and the kilojoule are both defined exactly in SI terms, so the ratio has no measurement uncertainty; 4.184 is just that ratio shown to 7 significant figures.
What is a kilojoule (kJ)?
1,000 joules.
How can I estimate kilocalories to kJ in my head?
Quick estimate: multiply by about 4.2 to get kJ from kilocalories; this is within 0.4% of the exact factor.
What is 40 kcal in kJ?
40 kcal = 167.36 kJ (since 40 × 4.184).
What is 200 kcal in kJ?
200 kcal = 836.8 kJ (since 200 × 4.184).
What is 3 kcal in kJ?
3 kcal = 12.552 kJ (since 3 × 4.184).
How many decimals should I keep when converting kcal to kJ?
Match the precision of your original measurement. For example, 41.84 kJ rounds to 41.8 kJ at 3 significant figures; keep more digits only for engineering or scientific work.
More in Energy converters
- kJ to Calories Converter
- Kilocalories to BTU Converter
- kJ to Joules Converter
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Method, review and disclaimer
Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers. Sources: NIST SP 811, Appendix B.8: conversion factors