Power Converter

Convert between power units

Amount

From

To

0.019904 BTU/s

rate：1 W = 0.00094782 BTU/s

Decimals 6 Thousands separator Scientific notation

Results in all units

21 W

Unit	Symbol	Value
Metric
Watts	W	21
Milliwatts	mW	21,000
Kilowatts	kW	0.021
Megawatts	MW	0.000021
Gigawatts	GW	2.1e-8
Joules/second	J/s	21
Metric horsepower	PS	0.028552
Imperial / US
Mechanical horsepower	hp	0.028161
BTU/hour	BTU/h	71.654974
BTU/second	BTU/s	0.019904
Foot pounds/second	ft·lb/s	15.488805
Calories/second	cal/s	5.01912
Kilocalories/hour	kcal/h	18.068834
Tons of refrigeration	TR	0.005971

Popular Power Conversions

Recent Conversions

Clear

21 Watts → 0.019904 BTU/second 🔋 Power

Trending Conversions

Just Converted

51 Foot pounds/second → 69,146.7154 Milliwatts 🔋 Power 21 Watts → 0.0199 BTU/second 🔋 Power 67 Tons of refrigeration → 173,791.1352 Foot pounds/second 🔋 Power 90 Megawatts → 77,437,858.5086 Kilocalories/hour 🔋 Power 5 Mechanical horsepower → 891.1327 Calories/second 🔋 Power 37 BTU/second → 52.3496 Mechanical horsepower 🔋 Power 498 Mechanical horsepower → 504.9071 Metric horsepower 🔋 Power 87 Metric horsepower → 0.064 Megawatts 🔋 Power 87 Joules/second → 0.087 Kilowatts 🔋 Power 31 Calories/second → 0.1297 Kilowatts 🔋 Power

Common Scenarios

Power conversion is frequently used in automotive manufacturing, appliance purchases, and air conditioning. Car enthusiasts compare kilowatts (kW) and horsepower (hp). When choosing AC units, understanding "tons of refrigeration (TR)" is necessary.

History & Background

The concept of power originated in the Industrial Revolution. After James Watt improved the steam engine, he proposed "horsepower" to demonstrate its efficiency. Later, to honor him, physics named the power of one joule per second a "watt" (W).

Conversion Details

Power conversion is based on the watt (W), representing work done per unit time.

Common conversions: 1 hp ≈ 745.7 W, 1 metric hp ≈ 735.5 W, 1 kW ≈ 1.341 hp.