Power Converter | Toolcroft

How to use this tool

Enter a power value. Type the power value you want to convert in either the From or To field.
Select units. Choose source and target power units from the dropdown menus.
Read the result. The converted power and the all-units values update instantly. Use the swap button to reverse the conversion.

Common power conversions

Value	Equivalent
1 kW	1,000,000 mW = 0.001 MW = 0.000001 GW
1 hp (mech)	745.7 W = 0.7457 kW
1 hp (metric/PS)	735.5 W = 0.7355 kW
1 hp (electrical)	746 W = 0.746 kW
1 kW	1.341 hp (mech) = 3,412 BTU/h
100 kW	134.1 hp (mech)
1 MW	1,000 kW = 1,341 hp
1 BTU/h	0.2931 W
12,000 BTU/h	3.517 kW = 1 ton of refrigeration (TR)

How power conversion works

All conversions use Watts as the base SI unit. The three horsepower variants are not identical: mechanical hp (745.7 W) is the standard US definition; metric hp (PS, 735.499 W) is used in Europe; electrical hp (746 W exactly) is used for electric motors per IEEE standards.

The “All units at this value” panel derives every listed result from the watt equivalent of whichever field you last edited, including the ton of refrigeration (TR). SI prefixes are case-sensitive: mW means milliwatts (0.001 W), while MW means megawatts (1,000,000 W); GW is one billion watts. Changing a unit keeps the active field's quantity as the conversion source.

Power vs energy

Power measures the rate of energy transfer (joules per second = watts). Energy is power multiplied by time: 1 kWh = 1 kW × 1 hour = 3,600,000 J. Use the Energy Converter for energy unit conversions.

Real-world power reference

Device / Application	Typical power
LED light bulb	9 W
Laptop (charging)	45 W
Desktop PC (gaming)	200–600 W
Microwave oven	1,000 W (1 kW)
Electric water heater	4,500 W (4.5 kW)
EV Level 2 charger (home)	7,200 W (7.2 kW)
Central air conditioner (3-ton)	3,500 W (3.5 kW)
Tesla Model 3 motor (peak)	239,000 W (239 kW ≈ 320 hp)

Three-phase power note

In industrial and commercial settings, three-phase AC power is standard. The apparent power formula is:

S = √3 × V_line × I × PF

Where S is apparent power (in VA or kVA), V_line is the line-to-line voltage (e.g., 480 V), I is current per phase, and PF is power factor (typically 0.8–0.95 for industrial loads). The distinction between kVA (apparent power) and kW (real power) matters for generator sizing and utility billing.

Frequently asked questions

How many watts is 1 horsepower?

It depends on the type: mechanical (imperial) horsepower = 745.7 W; metric horsepower (PS/CV) = 735.499 W; electrical horsepower = 746 W exactly. Car ratings in the US use mechanical hp; most European ratings use metric hp (PS).

How do I convert kW to BTU/h?

1 kW = 3,412.14 BTU/h. Multiply kilowatts by 3,412.14 to get BTU/h. This conversion is common for HVAC system sizing.

What is the difference between mechanical and metric horsepower?

Mechanical horsepower (used in the US) = 745.7 W. Metric horsepower (PS, used in Europe) = 735.5 W. They are close but not equal - a 200 PS engine is about 197 mechanical hp.

What does BTU/h measure?

BTU per hour (BTU/h) measures the rate of heat energy transfer, commonly used for air conditioners and furnaces. 1 BTU/h ≈ 0.293 W. A 12,000 BTU/h air conditioner is 1 ton of refrigeration (TR), about 3.52 kW.

What is a ton of refrigeration?

One ton of refrigeration (TR) is a cooling capacity of 12,000 BTU/h, equivalent to about 3.51685 kW using the same BTU definition as this converter. It is a cooling-rate unit, not a unit of mass.

What is the difference between mW and MW?

mW with a lowercase m means milliwatt, or 0.001 W. MW with an uppercase M means megawatt, or 1,000,000 W; one MW is one billion times larger than one mW.