Watts to Amps Conversion Calculator – DC & AC (Single & Three‑Phase) – Quick & Accurate

How to Convert Watts (W) to Amperes (A) – Simple and Advanced Calculators

The following two (basic and advanced) calculators can be used to calculate and convert the electric current in amperes from electric power in watts and voltage in volts.

In Advanced Watts to Amps Calculator, We can calculate the electric current in amperes, milliamperes or kiloamperes from electric power in in watts, milliwatts or kilowatts and RMS voltage in volts for DC circuits, AC, 1-Phase and 3-Phase circuits having the Line to Line voltage (Delta Connection), Line to Neutral voltage (Star Connection) and Power Factor (P.F). You may read more about the difference between Star (Y )and Delta (Δ) Connections.

In Simple Watts to Amps calculator, any two known values among three (P, I and V) can be used to calculate power in watts, current in amperes or voltage in volts.

Note 1: If you are on mobile phones device, click on the three dots “…” beside the “Advanced Calculator” to select the simple calculator. For better experience through mobile phones, use the calculator in landscape position.

Watts to Amps Calculator

• Advanced Calculator
• Simple Calculator

Advanced Watts to Amps Calculator

Simple Watts to Amps Calculator

Note 2: For higher values like, 5×10³, 10×10^-6, 1.6 x10¹², enter the value like this for scientific notation as 5e3, 10e-6, 1.6e12 etc.

DC Power in Watts to Amps Conversion

I = P ÷ V

AC Single Phase Power in Watts to Amps Conversion

I = P ÷ (V  x Cosθ)

AC Three Phase Power in Watts to Amps Conversion

Conversion with Line to Line Voltage (V_L-L)

I = P ÷ (√3 x V_L-L x Cosθ)

Conversion with Line to Neutral Voltage (V_L-N)

I = P ÷ (3 x V_L-N x Cosθ)

Where:

• P = Power in watts
• V = Voltage in volts
• I = Current in amperes
• Cosθ = Power factor in AC circuits
• V_L-L = Line to Line Voltage in 3-Phase Circuits
• V_L-N = Line to Neutral Voltage in 3-Phase Circuits

Typical Power Factor Values for Equipment and Appliances

For accurate calculation, use the exact value of power factor instead of the typical value by calculation or check the nameplate data rating of the appliance.

Electrical Equipment and Appliances		P.F = Cosθ
Motor & Transformer	Induction Motor at No Load	0.35
	Induction Motor at Full Load	0.85
	Transformer at No Load	0.15
Lamps	Incandescent Lamps	1.0
	Fluorescent Lamps (Uncompensated)	0.5
	Fluorescent Lamps (Compensated)	0.9
	Discharge Lamps	0.4 to 0.6
	Mercury Vapor Lamp	0.5
	Sodium Vapor Lamp	0.6-0.7
Ovens	Ovens using Resistance Elements	1.0
	Induction Heating Ovens (Compensated)	0.85
	Dielectric Type Heating Ovens	0.85
Welding	Resistance Type Soldering Machines	0.8 to 0.9
	Fixed 1-phase Arc Welding Set	0.5
	Arc Welding Motor Generating Set	0.7 to 0.9
	Arc Furnace	0.8 to 0.9
	Arc Welding Transformer Rectifier Set	0.7-0.8
AC-DC Drives & Converters	AC-DC Converters	0.95
	AC Drive	0.4-0.7
	DC Drive	0.6-0.9
Pure Resistive Load		1
Pure Inductive & Capacitive Load		0

How to Convert Watts to Amps?

The basic Amps to Watts calculator uses the Watt’s Law which states that “The total power of an electric circuit is equal to the product of electric current and voltage in that circuit”. i.e.

Current (I) in Amps = Power (P) in Watts ÷ Voltage (V) in Volts

I = P ÷ V

If we put the values of V and I in the above equations from Ohm’s law, we get the current as follow as well.

I = √(P ÷ R)

I = V ÷ R

Examples:

Current = Power ÷ Voltage

• I = 600W ÷ 120V = 5 A
• I = 2070W ÷ 5V = 9 W
• I = 48W ÷ 12V = 4 A

Equivalent Watts and Amps at 120V AC, 230V AC and 12V DC

The following table shows the different values of amperes and wattage for 120V and 230V AC and 12V DC at unity power factor “1”.

Current in Amp	Power in Watts	Voltage in Volts
1	120 W	120V AC
	230 W	230V AC
	12 W	12V DC
5	600 W	120V AC
	1150 W	230V AC
	60 W	12V DC
10	1200 W	120V AC
	2300 W	230V AC
	120 W	12V DC
15	1800 W	120V AC
	3450 W	230V AC
	180 W	12V DC
20	2400 W	120V AC
	4600 W	230V AC
	240 W	12V DC
30	3600 W	120V AC
	6900 W	230V AC
	360 W	12V DC
50	6000 W	120V AC
	11500 W	230V AC
	600 W	12V DC
70	8400 W	120V AC
	16100 W	230V AC
	840 W	12V DC
100	12000 W	120V AC
	23000 W	230V AC
	1200 W	12V DC

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