Convert 100 BTU/Hour (BTU/h) to Milliwatt (mW).

100 BTU/Hour equals 29,307.107017 Milliwatt. Multiply 100 by 293.0710701722.

100 BTU/Hour = 29,307.107017 Milliwatt

Worked example: converting BTU/Hour to Milliwatt

Step 1 — start with the formula. mW = BTU/h × 293.0710701722
Step 2 — substitute your figure. 100 BTU/h × 293.0710701722
Step 3 — read the result. 100 BTU/h = 29,307.107017 mW
Step 4 — check it in reverse. BTU/h = mW × 0.0034121416 returns Invalid BTU/h, which matches the figure you started with.

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29,307.107017

100 BTU/h = 29,307.107017 mW

Formula:

mW = BTU/h × 293.0710701722

With your value: 100 BTU/h = 29,307.10701722 mW

How big is that?

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

LED bulb (1/3.3 your value)30.7 BTU/h

Your value100 BTU/h

Laptop (2.2× your value)222 BTU/h

Microwave oven (34× your value)3.41e+3 BTU/h

Electric kettle (1.0e+2× your value)1.02e+4 BTU/h

Family car engine (3.1e+3× your value)3.07e+5 BTU/h

Other BTU/Hour to Milliwatt conversions

80 BTU/h to mW 85 BTU/h to mW 90 BTU/h to mW 96 BTU/h to mW 120 BTU/h to mW 150 BTU/h to mW 200 BTU/h to mW Full BTU/Hour to Milliwatt converter

BTU/Hour to Milliwatt Conversion Table

BTU/Hour (BTU/h)	Milliwatt (mW)
0.5	146.535535
1	293.07107
2	586.14214
5	1,465.355351
10	2,930.710702
15	4,396.066053
20	5,861.421403
25	7,326.776754
50	14,653.553509
100	29,307.107017
250	73,267.767543
500	146,535.535086
1000	293,071.070172

Milliwatt to BTU/Hour Conversion Table

Milliwatt (mW)	BTU/Hour (BTU/h)
0.5	0.001706
1	0.003412
2	0.006824
5	0.017061
10	0.034121
15	0.051182
20	0.068243
25	0.085304
50	0.170607
100	0.341214
250	0.853035
500	1.706071
1000	3.412142

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.

BTU/Hour (BTU/h)

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 BTU/Hour to Milliwatt

To convert from BTU/Hour (BTU/h) to Milliwatt (mW), multiply the value by 293.0710701722.

Formula: mW = BTU/h × 293.0710701722

Reverse: BTU/h = mW × 0.0034121416

Step-by-Step Example

Start with your value in BTU/Hour. For example: 5 BTU/h
Multiply by the conversion factor: 5 x 293.0710701722
The result is: 1,465.355351 mW

About BTU/Hour

The btu/hour (BTU/h) is a unit of power. One btu/hour equals 0.2930710702 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 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

What is 100 BTU/Hour in Milliwatt?

100 BTU/Hour equals 29,307.107017 Milliwatt.

How many Milliwatt are in 1 BTU/Hour?

There are exactly 293.0710701722 Milliwatt in 1 BTU/Hour. This means the conversion factor from BTU/Hour to Milliwatt is 293.0710701722.

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

The formula to convert BTU/Hour to Milliwatt is: mW = BTU/h × 293.0710701722. For example, to convert 10 BTU/Hour to Milliwatt, you would multiply 10 by 293.0710701722.

What is a BTU/Hour?