Kilojoule to Millijoule Converter

Energy Converter

27 units available

Decimals:

From

To

1,000,000

1 kJ = 1,000,000 mJ

Formula:

mJ = kJ × 1,000,000

With your value: 1 kJ = 1,000,000 mJ

How big is that?

Everyday references on a logarithmic scale, all expressed in kilojoule so you can sanity-check the result.

Heartbeat (1/1.0e+3 your value)0.00100 kJ

Your value1.00 kJ

AA battery charge (10× your value)10.0 kJ

Slice of bread (2.8e+2× your value)280 kJ

Daily food intake (8.4e+3× your value)8.40e+3 kJ

Litre of petrol (3.4e+4× your value)3.42e+4 kJ

Other Kilojoule to Millijoule conversions

2 kJ to mJ 3 kJ to mJ 4 kJ to mJ 5 kJ to mJ 6 kJ to mJ 7 kJ to mJ 8 kJ to mJ

Kilojoule to Millijoule Conversion Table

Kilojoule (kJ)	Millijoule (mJ)
0.5	500,000
1	1,000,000
2	2,000,000
5	5,000,000
10	10,000,000
15	15,000,000
20	20,000,000
25	25,000,000
50	50,000,000
100	100,000,000
250	250,000,000
500	500,000,000
1000	1,000,000,000

Millijoule to Kilojoule Conversion Table

Millijoule (mJ)	Kilojoule (kJ)
0.5	5.000000e-7
1	1.000000e-6
2	2.000000e-6
5	5.000000e-6
10	1.000000e-5
15	1.500000e-5
20	2.000000e-5
25	2.500000e-5
50	5.000000e-5
100	0.0001
250	0.00025
500	0.0005
1000	0.001

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Kilojoule (kJ)

Energy

Exact conversion

Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

Millijoule (mJ)

Energy

Exact conversion

Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

How to Convert Kilojoule to Millijoule

To convert from Kilojoule (kJ) to Millijoule (mJ), multiply the value by 1,000,000.

Formula: mJ = kJ × 1,000,000

Reverse: kJ = mJ × 0.000001

Step-by-Step Example

Start with your value in Kilojoule. For example: 5 kJ
Multiply by the conversion factor: 5 x 1,000,000
The result is: 5,000,000 mJ

About Kilojoule

The kilojoule (kJ) is a unit of energy and work. One kilojoule equals 1000 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

About Millijoule

The millijoule (mJ) is a unit of energy and work. One millijoule equals 0.001 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

Frequently Asked Questions

How many Millijoule are in 1 Kilojoule?

There are exactly 1,000,000 Millijoule in 1 Kilojoule. This means the conversion factor from Kilojoule to Millijoule is 1,000,000.

What is the formula to convert Kilojoule to Millijoule?

The formula to convert Kilojoule to Millijoule is: mJ = kJ × 1,000,000. For example, to convert 10 Kilojoule to Millijoule, you would multiply 10 by 1,000,000.

What is a Kilojoule?