Watt is the unit of power (symbol: W).
The watt unit is named after James Watt, the inventor of the steam engine.
One watt is defined as the energy consumption rate of one joule per second.
1W = 1J / 1s
One watt is also defined as the current flow of one ampere with voltage of one volt.
1W = 1V × 1A
Convert watt to milliwatt, kilowatt, megawatt, gigawatt, dBm, dBW.
Enter the power in one of the text boxes and press the Convert button:
| name | symbol | conversion | example |
|---|---|---|---|
| picowatt | pW | 1pW = 10-12 W | P = 10 pW |
| nanowatt | nW | 1nW = 10-9 W | P = 10 nW |
| microwatt | μW | 1μW = 10-6 W | P = 10 μW |
| milliwatt | mW | 1mW = 10-3 W | P = 10 mW |
| watt | W | - | P = 10 W |
| kilowatt | kW | 1kW = 103 W | P = 2 kW |
| megawatt | MW | 1MW = 106 W | P = 5 MW |
| gigawatt | GW | 1GW = 109 W | P = 5 GW |
The power P in kilowatts (kW) is equal to the power P in watts (W) divided by 1000:
P(kW) = P(W) / 1000
The power P in milliwatts (mW) is equal to the power P in watts (W) times 1000:
P(mW) = P(W) ⋅ 1000
The power P in decibel-milliwatts (dBm) is equal to 10 times base 10 logarithm of the power P in milliwatts (mW) divided by 1 milliwatt:
P(dBm) = 10 ⋅ log10( P(mW) / 1mW)
The current I in ampers (A) is equal to the power P in watts (W) divided by the voltage V in volts (V):
I(A) = P(W) / V(V)
The voltage V in volts (V) is equal to the power P in watts (W) divided by the current I in ampers (A):
V(V) = P(W) / I(A)
R(Ω) = P(W) / I(A)2
R(Ω) = V(V)2/ P(W)
P(BTU/hr) = 3.412142 ⋅ P(W)
E(J) = P(W) ⋅ t(s)
P(HP) = P(W) / 746
The real power P in watts (W) is equal to 1000 times the apparent power S in kilo-volt-amperes (kVA) times the power factor (PF) or cosine of the phase angle φ:
P(W) = 1000 ⋅ S(kVA) ⋅ PF = 1000 ⋅ S(kVA) ⋅ cos φ
The real power P in watts (W) is equal to the apparent power S in volt-amperes (VA) times the power factor (PF) or cosine of the phase angle φ:
P(W) = S(VA) ⋅ PF = S(VA) ⋅ cos φ
How many watts does a house use? How many watts does a TV use? How many watts does a refrigerator use?
| Electric component | Typical power consumption in watts |
|---|---|
| LCD TV | 30..300 W |
| LCD monitor | 30..45 W |
| PC desktop computer | 300..400 W |
| Laptop computer | 40..60 W |
| Refrigerator | 150..300 W (when active) |
| Light bulb | 25..100 W |
| Fluorescent light | 15..60 W |
| Halogen light | 30..80 W |
| Speaker | 10..300 W |
| Microwave | 100..1000 W |
| Air conditioner | 1..2 kW |
