Convert 18 Watt (W) to BTU/Hour (BTU/h).

18 Watt equals 61.418549 BTU/Hour. Multiply 18 by 3.4121416331.

18 Watt = 61.418549 BTU/Hour

Worked example: converting Watt to BTU/Hour

Step 1 — start with the formula. BTU/h = W × 3.4121416331
Step 2 — substitute your figure. 18 W × 3.4121416331
Step 3 — read the result. 18 W = 61.418549 BTU/h
Step 4 — check it in reverse. W = BTU/h × 0.2930710702 returns 18 W, which matches the figure you started with.

Power Converter

22 units available

Decimals:

From

To

61.418549

18 W = 61.418549 BTU/h

Formula:

BTU/h = W × 3.4121416331

With your value: 18 W = 61.4185494 BTU/h

How big is that?

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

LED bulb (1/2.0 your value)9.00 W

Your value18.0 W

Laptop (3.6× your value)65.0 W

Microwave oven (56× your value)1.00e+3 W

Electric kettle (1.7e+2× your value)3.00e+3 W

Family car engine (5.0e+3× your value)9.00e+4 W

Other Watt to BTU/Hour conversions

13 W to BTU/h 14 W to BTU/h 15 W to BTU/h 16 W to BTU/h 20 W to BTU/h 21 W to BTU/h 24 W to BTU/h Full Watt to BTU/Hour converter

Watt to BTU/Hour Conversion Table

Watt (W)	BTU/Hour (BTU/h)
0.5	1.706071
1	3.412142
2	6.824283
5	17.060708
10	34.121416
15	51.182124
20	68.242833
25	85.303541
50	170.607082
100	341.214163
250	853.035408
500	1,706.070817
1000	3,412.141633

BTU/Hour to Watt Conversion Table

BTU/Hour (BTU/h)	Watt (W)
0.5	0.146536
1	0.293071
2	0.586142
5	1.465355
10	2.930711
15	4.396066
20	5.861421
25	7.326777
50	14.653554
100	29.307107
250	73.267768
500	146.535535
1000	293.07107

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.

Watt (W)

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/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

Standards and context behind Watt to BTU/Hour

HVAC ratings: Air-conditioning capacity is quoted in BTU/h in the US and watts elsewhere; 1 W = 3.41214 BTU/h.

How to Convert Watt to BTU/Hour

To convert from Watt (W) to BTU/Hour (BTU/h), multiply the value by 3.4121416331.

Formula: BTU/h = W × 3.4121416331

Reverse: W = BTU/h × 0.2930710702

Step-by-Step Example

Start with your value in Watt. For example: 5 W
Multiply by the conversion factor: 5 x 3.4121416331
The result is: 17.060708 BTU/h

About Watt

The watt (W) is a unit of power. One watt 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 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.

Frequently Asked Questions

What is 18 Watt in BTU/Hour?

18 Watt equals 61.418549 BTU/Hour.

How many BTU/Hour are in 1 Watt?

There are exactly 3.4121416331 BTU/Hour in 1 Watt. This means the conversion factor from Watt to BTU/Hour is 3.4121416331.

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

The formula to convert Watt to BTU/Hour is: BTU/h = W × 3.4121416331. For example, to convert 10 Watt to BTU/Hour, you would multiply 10 by 3.4121416331.

What is a Watt?