Convert Kilojoules to Megajoules
1 kilojoule (kJ) equals 0.001 megajoules (MJ).
1 kJ = 0.001 MJ
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk kilojoule to megajoule converter to paste a column from Excel.
How to Convert Kilojoule to Megajoule
- 1 kJ = 0.001 MJ
- 1 MJ = 1000 kJ
- Example: convert 15 kJ to MJ: 15 kJ = 15 × 0.001 MJ = 0.015 MJ
Formula
MJ = kJ ÷ 1000
Derivation from SI units:
- 1 kJ = 10³ J
- 1 MJ = 10⁶ J
- 1 kJ = 1000 J ÷ 1000000 J per MJ = 0.001 MJ
Both units are defined exactly, so the factor is exact. Kilojoule definition: kilojoule; Megajoule definition: megajoule.
Worked examples
- A reading of 100 kJ converts to 0.1 MJ.
100 kJ × 0.001 = 0.1 MJ - A value of 1000 kJ is 1 MJ.
1000 kJ × 0.001 = 1 MJ
Kilojoule to Megajoule conversion table
| Kilojoules (kJ) | Megajoules (MJ) |
|---|---|
| 1 kJ | 0.001 MJ |
| 4.184 kJ | 0.004184 MJ |
| 10 kJ | 0.01 MJ |
| 50 kJ | 0.05 MJ |
| 100 kJ | 0.1 MJ |
| 250 kJ | 0.25 MJ |
| 500 kJ | 0.5 MJ |
| 840 kJ | 0.84 MJ |
| 1000 kJ | 1 MJ |
| 2000 kJ | 2 MJ |
| 8700 kJ | 8.7 MJ |
| 10000 kJ | 10 MJ |
Where it's used
Kilojoules are used for nutrition labels (kJ per serving), while megajoules appear in fuel heating values (natural gas ≈ 38 MJ/m³, diesel ≈ 45 MJ/kg). Both measure energy, work and heat, so the conversion is a fixed factor.
Kilojoule to other energy units
| Conversion | 1 kJ equals |
|---|---|
| kilojoule to joule | 1000 J |
| kilojoule to megajoule | 0.001 MJ |
| kilojoule to calorie | 239.0057361 cal |
| kilojoule to kilocalorie | 0.2390057361 kcal |
| kilojoule to watt-hour | 0.2777777778 Wh |
| kilojoule to kilowatt-hour | 0.0002777777778 kWh |
| kilojoule to BTU | 0.9478171203 BTU |
| kilojoule to therm | 0.00000948043428 thm |
| kilojoule to electronvolt | 6.241509074 × 10²¹ eV |
| kilojoule to foot-pound | 737.5621493 ft·lbf |
| kilojoule to erg | 10000000000 erg |
Frequently asked questions
How many megajoules are in 1 kilojoule?
1 kJ = 0.001 MJ.
How do I convert kilojoules to megajoules?
Multiply the value in kJ by 0.001, or divide it by 1000. For example, 15 kJ × 0.001 = 0.015 MJ.
Is the kJ to MJ conversion exact?
Yes. Both units are defined exactly, and 1 kJ is exactly 0.001 MJ.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Kilojoules to Megajoules. Retrieved October 17, 2026, from https://scientificconverters.com/energy/kilojoules-to-megajoules/
IEEE
Scientific Converters, "Convert Kilojoules to Megajoules," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/kilojoules-to-megajoules/