To convert kilojoules to joules, multiply by 1000.
The calculation uses 1 kJ = 1000 J. Results are displayed to at most 10 significant digits. Definitions can be exact while a displayed decimal is rounded. Match the displayed precision to your original measurement.
The formula
value in J = value in kJ × 1000
kJ- Input unit: kilojoules
J- Output unit: joules
How to use this calculator
- Enter a value in kJ.
- Multiply by the stored conversion factor.
- Read the result in J; divide by the same factor to convert back.
Worked examples
Worked conversion
1 kJ × 1000 ≈ 1000 J.
Reverse conversion
1000 J ÷ 1000 ≈ 1 kJ. Rounding intermediate values can change the last displayed digit.
Frequently asked questions
What factor does this converter use?
It uses 1000 J per kJ.
Why can another converter show a slightly different answer?
Check the unit convention first (such as US versus Imperial or decimal versus binary), then compare rounding. Measurement uncertainty is separate from the unit conversion.
kJ to J table
| kJ | J (rounded) |
|---|---|
| 0 | 0 |
| 1 | 1000 |
| 2 | 2000 |
| 5 | 5000 |
| 10 | 10000 |
| 100 | 100000 |
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