Convert 150 Milliwatt (mW) to BTU/Second (BTU/s).

150 Milliwatt equals 0.000142 BTU/Second. Multiply 150 by 9.478171e-7.

150 Milliwatt = 0.000142 BTU/Second

Worked example: converting Milliwatt to BTU/Second

Step 1 — start with the formula. BTU/s = mW × 9.478171e-7
Step 2 — substitute your figure. 150 mW × 9.478171e-7
Step 3 — read the result. 150 mW = 0.000142 BTU/s
Step 4 — check it in reverse. mW = BTU/s × 1,055,055.85262 returns 149.8179 mW, which matches the figure you started with.

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From

To

0.000142

150 mW = 0.000142 BTU/s

Formula:

BTU/s = mW × 9.478171e-7

With your value: 150 mW = 0.00014217 BTU/s

How big is that?

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

Your value150 mW

LED bulb (60× your value)9.00e+3 mW

Laptop (4.3e+2× your value)6.50e+4 mW

Microwave oven (6.7e+3× your value)1.00e+6 mW

Electric kettle (2.0e+4× your value)3.00e+6 mW

Family car engine (6.0e+5× your value)9.00e+7 mW

Other Milliwatt to BTU/Second conversions

90 mW to BTU/s 96 mW to BTU/s 100 mW to BTU/s 120 mW to BTU/s 200 mW to BTU/s 500 mW to BTU/s 1000 mW to BTU/s Full Milliwatt to BTU/Second converter

Milliwatt to BTU/Second Conversion Table

Milliwatt (mW)	BTU/Second (BTU/s)
0.5	4.739086e-7
1	9.478171e-7
2	1.895634e-6
5	4.739086e-6
10	9.478171e-6
15	1.421726e-5
20	1.895634e-5
25	2.369543e-5
50	4.739086e-5
100	9.478171e-5
250	0.000237
500	0.000474
1000	0.000948

BTU/Second to Milliwatt Conversion Table

BTU/Second (BTU/s)	Milliwatt (mW)
0.5	527,527.92631
1	1,055,055.85262
2	2,110,111.70524
5	5,275,279.2631
10	10,550,558.5262
15	15,825,837.7893
20	21,101,117.0524
25	26,376,396.3155
50	52,752,792.631
100	105,505,585.262
250	263,763,963.155
500	527,527,926.31
1000	1,055,055,852.62

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.

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

BTU/Second (BTU/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

How to Convert Milliwatt to BTU/Second

To convert from Milliwatt (mW) to BTU/Second (BTU/s), multiply the value by 9.478171e-7.

Formula: BTU/s = mW × 9.478171e-7

Reverse: mW = BTU/s × 1,055,055.85262

Step-by-Step Example

Start with your value in Milliwatt. For example: 5 mW
Multiply by the conversion factor: 5 x 9.478171e-7
The result is: 4.739086e-6 BTU/s

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.

About BTU/Second

The btu/second (BTU/s) is a unit of power. One btu/second equals 1055.055853 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

What is 150 Milliwatt in BTU/Second?

150 Milliwatt equals 0.000142 BTU/Second.

How many BTU/Second are in 1 Milliwatt?

There are exactly 9.478171e-7 BTU/Second in 1 Milliwatt. This means the conversion factor from Milliwatt to BTU/Second is 9.478171e-7.

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

The formula to convert Milliwatt to BTU/Second is: BTU/s = mW × 9.478171e-7. For example, to convert 10 Milliwatt to BTU/Second, you would multiply 10 by 9.478171e-7.

What is a Milliwatt?