Kilocalories to Joules Converter
Quick answer: To convert kilocalories to joules, multiply by 4,184. For example, 10 kcal is 41,840 J. One kilocalorie equals 4,184 J.
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Use the Kilocalories to Joules Converter
Kilocalories to Joules formula and what each symbol means
J = kcal × 4,184
| Symbol | Meaning |
|---|---|
| kcal | Kilocalorie |
| J | Joule |
Kilocalories to Joules examples
1 kcal
1 kcal × 4,184 = 4,184 J.
10 kcal
10 kcal × 4,184 = 41,840 J.
100 kcal
100 kcal × 4,184 = 418,400 J.
Kilocalories compared with Joules
One kcal is 4,184 times as large as one J, so your number gets bigger when you convert kilocalories to joules and smaller when you convert back. If the answer is not larger than what you typed, you divided instead of multiplying.
About kilocalories and joules
Kilocalorie (kcal): The thermochemical kilocalorie, exactly 4,184 joules, used for food energy. Joule (J): The SI unit of energy, one newton metre.
Where kilocalories to joules conversions are used
Food labels show kilocalories or kilojoules, and electricity bills use kilowatt-hours. Gas and heating are often billed in therms, BTU or megajoules.
How to calculate Kilocalories to Joules step by step
- Enter the value in kcal (the starting unit).
- Multiply by 4,184, because 1 kcal = 4,184 J.
- The product is the value in J. To go back, divide by 4,184 or multiply by 0.0002390057.
Popular energy conversions
How to read your Kilocalories to Joules result
Quick estimate: multiply by about 4,200 to get joules from kilocalories; this is within 0.4% of the exact factor. The joule is the SI unit of energy.
| KILOCALORIES | JOULES |
|---|---|
| 1 | 4,184 |
| 2 | 8,368 |
| 5 | 20,920 |
| 10 | 41,840 |
| 20 | 83,680 |
| 50 | 209,200 |
| 100 | 418,400 |
| 1,000 | 4,184,000 |
Joules to Kilocalories: quick table
| JOULES | KILOCALORIES |
|---|---|
| 1 | 0.0002390057 |
| 5 | 0.001195029 |
| 10 | 0.002390057 |
| 25 | 0.005975143 |
| 50 | 0.01195029 |
| 100 | 0.02390057 |
| 250 | 0.05975143 |
| 500 | 0.1195029 |
Common mistakes when calculating Kilocalories to Joules
- Mixing the small calorie (cal) with the food Calorie (kcal): the difference is a factor of 1,000.
- Dividing when you should multiply: from kcal to J multiply by 4,184; from J to kcal divide by 4,184.
Kilocalories to Joules FAQ
How many J are in 1 kcal?
1 kcal equals 4,184 J.
How many kcal are in 1 J?
1 J equals 0.0002390057 kcal.
Is 1 kcal = 4,184 J an exact conversion?
Yes. The kilocalorie and the joule 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 kilocalorie (kcal)?
The thermochemical kilocalorie, exactly 4,184 joules, used for food energy.
How can I estimate kilocalories to joules in my head?
Quick estimate: multiply by about 4,200 to get joules from kilocalories; this is within 0.4% of the exact factor.
What is 15 kcal in joules?
15 kcal = 62,760 J (since 15 × 4,184).
What is 75 kcal in joules?
75 kcal = 313,800 J (since 75 × 4,184).
What is 300 kcal in joules?
300 kcal = 1,255,200 J (since 300 × 4,184).
How many decimals should I keep when converting kcal to J?
Match the precision of your original measurement. For example, 41,840 J rounds to 41,800 J at 3 significant figures; keep more digits only for engineering or scientific work.
More in Energy converters
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- kJ to Kilocalories 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