Quick answer: 1 Kilojoule in Joule
1 kJ equals 1000 J. To convert Kilojoule to Joule, multiply by 1000 using the free calculator above — no signup needed.
Energy & Work units
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About Energy & Work Converter
The Energy & Work Converter converts between 7 different units, including Joule, Kilojoule, Calorie, Kilocalorie (kcal), Watt-hour (Wh). The base unit is the Joule, and every other unit on this page is defined as an exact multiple of it. Type any value into the calculator above to convert instantly — free, unlimited, no signup and nothing to install.
Common equivalents: 1 Joule = 0.001 Kilojoule, 0.239006 Calorie, 0.000239006 Kilocalorie (kcal).
Scale of this category: the smallest unit is the Joule (J) and the largest is the Kilowatt-hour (kWh) (kWh).
Last updated: 2026-09-15
Energy & Work conversion factors
| Unit | Symbol | Value in Joule |
|---|---|---|
| Joule | J | 1 J = 1 J |
| Kilojoule | kJ | 1 kJ = 1000 J |
| Calorie | cal | 1 cal = 4.184 J |
| Kilocalorie (kcal) | kcal | 1 kcal = 4184 J |
| Watt-hour (Wh) | Wh | 1 Wh = 3600 J |
| Kilowatt-hour (kWh) | kWh | 1 kWh = 3600000 J |
| BTU | BTU | 1 BTU = 1055.06 J |
Worked Examples
See exactly how the conversion works with real numbers, step by step.
How much is 1 Kilojoule in Joule?
- Multiply 1 by the conversion factor 1000
- 1 Kilojoule = 1000 Joule
How much is 5 Kilojoule in Joule?
- Multiply 5 by the conversion factor 1000
- 5 Kilojoule = 5000 Joule
How much is 25 Kilojoule in Joule?
- Multiply 25 by the conversion factor 1000
- 25 Kilojoule = 25000 Joule
Quick Conversion Reference Table
| Kilojoule (kJ) | Joule (J) |
|---|---|
| 1 kJ (Kilojoule) | 1000 J (Joule) |
| 2 kJ (Kilojoule) | 2000 J (Joule) |
| 5 kJ (Kilojoule) | 5000 J (Joule) |
| 10 kJ (Kilojoule) | 10000 J (Joule) |
| 20 kJ (Kilojoule) | 20000 J (Joule) |
| 50 kJ (Kilojoule) | 50000 J (Joule) |
| 100 kJ (Kilojoule) | 100000 J (Joule) |
| 500 kJ (Kilojoule) | 500000 J (Joule) |
| 1000 kJ (Kilojoule) | 1000000 J (Joule) |
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How to Use This Converter
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FAQ
How much is 1 Kilojoule in Joule?
1 Kilojoule = 1000 Joule.
How do I convert Kilojoule to Joule?
Enter your value in Kilojoule into the converter above and the result in Joule appears instantly. 1 kJ equals 1000 J — just multiply your value by 1000.
What is the formula for Kilojoule to Joule?
The formula is: value in Joule = value in Kilojoule × 1000. For example, 5 kJ × 1000 = 5000 J.
Is this Kilojoule to Joule converter free and accurate?
Yes. This Kilojoule to Joule converter is 100% free, uses the exact international conversion factor (1000), and works on any device with no signup.
How do I convert Joule back to Kilojoule?
To convert back, divide by 1000 (or multiply by 0.001). You can also use our dedicated How Many Kilojoule in 1 Joule? page for instant results.
Do I need to download an app or sign up?
No. The converter runs entirely in your browser — nothing to install, no account, no fees. It even keeps working offline once the page has loaded.
Which Energy & Work units are supported?
This converter supports 7 units: Joule, Kilojoule, Calorie, Kilocalorie (kcal), Watt-hour (Wh), Kilowatt-hour (kWh), BTU.