How to Convert Megajoules to Joules (MJ to J)
Energy conversions link food labels in kJ and kcal, SP Group bills in kWh and air-conditioner capacity in BTU. This guide shows how to convert megajoules into joules by hand, with examples and a quick-reference table.
The conversion
To convert megajoules to joules, multiply the value by 1,000,000. To go the other way, divide by the same number (or multiply by 1.000000e-06). For a quick estimate, multiply by about 1,000,000.
Joules = megajoules × 1,000,000
Worked examples
- 3 MJ = 3,000,000 J
- 12.5 MJ = 12,500,000 J
- 75 MJ = 75,000,000 J
Megajoules to Joules table
| Megajoules | Joules |
|---|---|
| 1 MJ | 1,000,000 J |
| 2 MJ | 2,000,000 J |
| 5 MJ | 5,000,000 J |
| 10 MJ | 10,000,000 J |
| 20 MJ | 20,000,000 J |
| 25 MJ | 25,000,000 J |
| 50 MJ | 50,000,000 J |
| 100 MJ | 100,000,000 J |
| 250 MJ | 250,000,000 J |
| 500 MJ | 500,000,000 J |
| 1,000 MJ | 1,000,000,000 J |
Common questions
Is MJ to J exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Joules to Megajoules converter.
Mistakes to avoid
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the Megajoules to Joules Converter or browse all energy converters.
Run your own numbers: Megajoules to Joules Converter