Watts to Amps Electrical Conversion Calculator
Enter the power and voltage to convert watts to amps for DC, single-phase AC, and three-phase AC circuits.
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Try our amps to watts calculator.
How to Convert Watts to Amps
Converting watts to amps can be done using the power formula, which states that I = P ÷ E, where P is power measured in watts, I is current measured in amps, and E is voltage measured in volts.
Given this, to find amps given power and voltage use the following formula:
I(A) = P(W) / V(V)
Thus, the current I in amps is equal to the power P in watts divided by the voltage V in volts.
For example, find the amperage of 1200 watts at 120 volts
current = power ÷ voltage
current = 1200W ÷ 120V
current = 10A
How Many Watts Are in an Amp
Using the formula above you can figure out how many watts there are per amp. At 120 volts, 120 watts are equal to 1 amp, but this will change depending on the voltage of the circuit.
For instance, at 240 volts, 240 watts are equal to 1 amp.
Single-Phase AC Circuit Watts to Amps Conversion
Converting watts to amps for a single-phase AC circuit with power factor uses a slightly different formula.
I(A) = P(W) / V(V) × PF
In other words, the current I in amps is equal to the power P in watts divided by the voltage V in volts multiplied by the power factor PF. If you’re unsure what the power factor is then a power factor calculator can help.
Three-Phase AC Circuit Watts to Amps Conversion
Using Line to Line Voltage
For three-phase AC circuits where the line to line voltage is known, the formula to convert watts to amps is:
I(A) = P(W) / VL-L(V) × PF × √3
The current I in amps is equal to the power P in watts divided by the line to line voltage V in volts multiplied by the power factor PF multiplied by the square root of 3.
Using Line to Neutral Voltage
For three-phase AC circuits where the line to neutral voltage is known, the formula to convert watts to amps is:
I(A) = P(W) / VL-N(V) × PF × 3
The current I in amps is equal to the power P in watts divided by the voltage V in volts multiplied by the power factor PF multiplied by 3.
How to Convert Watts and Ohms to Amps
It is also possible to convert watts to amps if the resistance of the circuit is known using the formula:
I(A) = √(P(W) × R(Ω))
The current I in amps is equal to the square root of the power P in watts multiplied by the resistance R in ohms.
It is not possible to convert watts directly to amps without also knowing voltage or resistance.
Because 1 kilowatt is equal to 1,000 watts, it is possible to use the formulas above to also convert kW to amps, but watts need to be converted to kW first. Use our kW to amps calculator to solve for kilowatts.
Equivalent Watts and Amps at 120V AC
|50 Watts||0.4167 Amps||120 Volts|
|100 Watts||0.8333 Amps||120 Volts|
|150 Watts||1.25 Amps||120 Volts|
|200 Watts||1.667 Amps||120 Volts|
|250 Watts||2.083 Amps||120 Volts|
|300 Watts||2.5 Amps||120 Volts|
|350 Watts||2.917 Amps||120 Volts|
|400 Watts||3.333 Amps||120 Volts|
|450 Watts||3.75 Amps||120 Volts|
|500 Watts||4.167 Amps||120 Volts|
|600 Watts||5 Amps||120 Volts|
|700 Watts||5.833 Amps||120 Volts|
|800 Watts||6.667 Amps||120 Volts|
|900 Watts||7.5 Amps||120 Volts|
|1000 Watts||8.333 Amps||120 Volts|
|1100 Watts||9.167 Amps||120 Volts|
|1200 Watts||10 Amps||120 Volts|
|1300 Watts||10.833 Amps||120 Volts|
|1400 Watts||11.667 Amps||120 Volts|
|1500 Watts||12.5 Amps||120 Volts|
|1600 Watts||13.333 Amps||120 Volts|
|1700 Watts||14.167 Amps||120 Volts|
|1800 Watts||15 Amps||120 Volts|
|1900 Watts||15.833 Amps||120 Volts|
|2000 Watts||16.667 Amps||120 Volts|
|2100 Watts||17.5 Amps||120 Volts|
|2200 Watts||18.333 Amps||120 Volts|
|2300 Watts||19.167 Amps||120 Volts|
|2400 Watts||20 Amps||120 Volts|
|2500 Watts||20.833 Amps||120 Volts|
Equivalent Watts and Amps at 12V DC
|5 Watts||0.4167 Amps||12 Volts|
|10 Watts||0.8333 Amps||12 Volts|
|15 Watts||1.25 Amps||12 Volts|
|20 Watts||1.667 Amps||12 Volts|
|25 Watts||2.083 Amps||12 Volts|
|30 Watts||2.5 Amps||12 Volts|
|35 Watts||2.917 Amps||12 Volts|
|40 Watts||3.333 Amps||12 Volts|
|45 Watts||3.75 Amps||12 Volts|
|50 Watts||4.167 Amps||12 Volts|
|60 Watts||5 Amps||12 Volts|
|70 Watts||5.833 Amps||12 Volts|
|80 Watts||6.667 Amps||12 Volts|
|90 Watts||7.5 Amps||12 Volts|
|100 Watts||8.333 Amps||12 Volts|
|110 Watts||9.167 Amps||12 Volts|
|120 Watts||10 Amps||12 Volts|
|130 Watts||10.833 Amps||12 Volts|
|140 Watts||11.667 Amps||12 Volts|
|150 Watts||12.5 Amps||12 Volts|
|160 Watts||13.333 Amps||12 Volts|
|170 Watts||14.167 Amps||12 Volts|
|180 Watts||15 Amps||12 Volts|
|190 Watts||15.833 Amps||12 Volts|
|200 Watts||16.667 Amps||12 Volts|
|210 Watts||17.5 Amps||12 Volts|
|220 Watts||18.333 Amps||12 Volts|
|230 Watts||19.167 Amps||12 Volts|
|240 Watts||20 Amps||12 Volts|
|250 Watts||20.833 Amps||12 Volts|