Joule/Second to Milliwatt Converter

Power Converter

22 units available

Decimals:

From

To

1,000

1 J/s = 1,000 mW

Formula:

mW = J/s × 1,000

With your value: 1 J/s = 1,000 mW

How big is that?

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

Your value1.00 J/s

LED bulb (9.0× your value)9.00 J/s

Laptop (65× your value)65.0 J/s

Microwave oven (1.0e+3× your value)1.00e+3 J/s

Electric kettle (3.0e+3× your value)3.00e+3 J/s

Family car engine (9.0e+4× your value)9.00e+4 J/s

Other Joule/Second to Milliwatt conversions

2 J/s to mW 3 J/s to mW 4 J/s to mW 5 J/s to mW 6 J/s to mW 7 J/s to mW 8 J/s to mW

Joule/Second to Milliwatt Conversion Table

Joule/Second (J/s)	Milliwatt (mW)
0.5	500
1	1,000
2	2,000
5	5,000
10	10,000
15	15,000
20	20,000
25	25,000
50	50,000
100	100,000
250	250,000
500	500,000
1000	1,000,000

Milliwatt to Joule/Second Conversion Table

Milliwatt (mW)	Joule/Second (J/s)
0.5	0.0005
1	0.001
2	0.002
5	0.005
10	0.01
15	0.015
20	0.02
25	0.025
50	0.05
100	0.1
250	0.25
500	0.5
1000	1

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.

Joule/Second (J/s)

Power

Exact conversion

Derived from the watt (1 W = 1 J/s).

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

Milliwatt (mW)

Power

Exact conversion

Derived from the watt (1 W = 1 J/s).

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 Joule/Second to Milliwatt

To convert from Joule/Second (J/s) to Milliwatt (mW), multiply the value by 1,000.

Formula: mW = J/s × 1,000

Reverse: J/s = mW × 0.001

Step-by-Step Example

Start with your value in Joule/Second. For example: 5 J/s
Multiply by the conversion factor: 5 x 1,000
The result is: 5,000 mW

About Joule/Second

The joule/second (J/s) is a unit of power. One joule/second equals 1 watt. UnitConvertLab converts it against every other power unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

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

About Milliwatt

The milliwatt (mW) is a unit of power. One milliwatt equals 0.001 watts. UnitConvertLab converts it against every other power unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

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

Frequently Asked Questions

How many Milliwatt are in 1 Joule/Second?

There are exactly 1,000 Milliwatt in 1 Joule/Second. This means the conversion factor from Joule/Second to Milliwatt is 1,000.

What is the formula to convert Joule/Second to Milliwatt?

The formula to convert Joule/Second to Milliwatt is: mW = J/s × 1,000. For example, to convert 10 Joule/Second to Milliwatt, you would multiply 10 by 1,000.

What is a Joule/Second?