Kilocalorie to Kilojoule Converter
Energy · unit-converter
Convert Kilocalorie to Kilojoule with fixed input and output units, a step-by-step formula line, and reference tables. Factors are joule-based; food energy uses thermochemical calories. The full Energy Converter also includes MMBtu, toe, thermal kWh, and MeV/GeV.
Calculator
From: Kilocalorie (kcal)
To: Kilojoule (kj)
About Kilocalorie
The kilocalorie (kcal) is 1,000 calories in the nutrition sense—often labeled “Calorie” on food packaging. Here 1 kcal = 4,184 J (thermochemical calorie definition used in this tool).
About Kilojoule
One kilojoule is 1,000 J. Scientific and engineering contexts often use kJ alongside joules.
How to convert kilocalories to kilojoules
1 kilocalorie is equal to 4.184 kilojoule when both are expressed in joule-equivalents:
1 kcal = (4,184 J ÷ 1,000 J) kj = 4.184 kj
Each kilocalorie is defined as 4,184 J and each kilojoule as 1,000 J in this tool, so one kcal equals 4,184 ÷ 1,000 kj = 4.184 kj.
Let d(kcal) be the numeric amount in Kilocalorie (kcal), and d(kj) the amount in Kilojoule (kj). Then:
d(kj) = d(kcal) × (4,184 / 1,000)
Equivalently, divide by how many kcal fit into one kj (joules per kj divided by joules per kcal):
d(kj) = d(kcal) ÷ 0.23900573613767
Or: kilojoule = kilocalorie ÷ 0.23900573613767
Examples
Example #1: Convert 1 kcal to kilojoule
1 kcal = 1 kcal × (4,184/1,000) kj = 4.184 kj
1 kcal = 1 kcal ÷ 0.23900573613767 = 4.184 kj
Example #2: Convert 10 kcal to kilojoule
10 kcal = 10 kcal × (4,184/1,000) kj = 41.84 kj
10 kcal = 10 kcal ÷ 0.23900573613767 = 41.84 kj
Summary
To convert Kilocalorie to Kilojoule, multiply the value in kcal by the ratio of joules per kcal divided by joules per kj. Equivalently: value_kj = value_kcal × (4184 / 1000). Numerically, 1 kcal equals 4.184 kj.
Relationship context
You are converting between food / nutrition energy (calories) (Kilocalories) and SI energy (joules) (Kilojoules). All values are mapped through joules first. The numeric factor is 4.184000e+0.
Conversion tables
| Kilocalorie (kcal) | Kilojoule (kj) |
|---|---|
| 0.1 | 0.4184 |
| 1 | 4.184 |
| 2 | 8.368 |
| 3 | 12.552 |
| 4 | 16.736 |
| 5 | 20.92 |
| 6 | 25.104 |
| 7 | 29.288 |
| 8 | 33.472 |
| 9 | 37.656 |
| Kilocalorie (kcal) | Kilojoule (kj) |
|---|---|
| 10 | 41.84 |
| 20 | 83.68 |
| 30 | 125.52 |
| 40 | 167.36 |
| 50 | 209.2 |
| 60 | 251.04 |
| 70 | 292.88 |
| 80 | 334.72 |
| 90 | 376.56 |
| 100 | 418.4 |