Kilojoules to Joules Converter
Convert kilojoules to joules — multiply by one thousand. Results update as you type; exact factors shown.
One kilojoule is 1,000 joules — see the exact factor, not a rounded rule of thumb.
How the kilojoules to joules converter works
Energy converts through the joule. A thermochemical calorie is exactly 4.184 J, so a food Calorie (kcal) is 4.184 kJ. A kilowatt-hour is exactly 3.6 MJ. A BTU is 1,055.056 J and a US therm is 100,000 BTU.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common energy conversions
| From | To | Units |
|---|---|---|
| 0.5 kJ | 500 J | kilojoules to joules |
| 1 kJ | 1,000 J | kilojoule to joules |
| 5 kJ | 5,000 J | kilojoules to joules |
| 10 kJ | 10,000 J | kilojoules to joules |
| 50 kJ | 50,000 J | kilojoules to joules |
| 100 kJ | 100,000 J | kilojoules to joules |
| 250 kJ | 250,000 J | kilojoules to joules |
| 500 kJ | 500,000 J | kilojoules to joules |
| 1,000 kJ | 1,000,000 J | kilojoules to joules |
| 2,000 kJ | 2,000,000 J | kilojoules to joules |
| 8,700 kJ | 8,700,000 J | kilojoules to joules |
| 10,000 kJ | 10,000,000 J | kilojoules to joules |
Units in this converter and their exact factors
| Unit | Symbol | One unit in joules |
|---|---|---|
| joule | J | 1 joule |
| kilojoule | kJ | 1,000 joule |
| megajoule | MJ | 1,000,000 joule |
| calorie (thermochemical) | cal | 4.184 joule |
| kilocalorie (food Calorie) | kcal | 4,184 joule |
| watt-hour | Wh | 3,600 joule |
| kilowatt-hour | kWh | 3,600,000 joule |
| British thermal unit | BTU | 1,055.05585262 joule |
| therm (US) | thm | 105,505,585.262 joule |
| foot-pound | ft·lb | 1.3558179483 joule |
FAQFrequently asked questions about energy conversion
How many joules in a kilojoule?
Exactly 1,000.
What is 8,700 kJ?
The Australian daily energy intake reference for an adult — 8.7 million joules.
What is a joule?
The energy to push with one newton over one metre — very small, which is why food and fuel use kilojoules or megajoules.
Are food calories joules?
A food Calorie is 4.184 kJ, so a 2,000 Calorie diet is about 8,368 kJ.
Which does Australia use on labels?
Kilojoules, by law, with Calories sometimes shown alongside.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.