Watts to Amps Calculator & Conversion – DC/AC (1 & 3 Phase)
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
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 (VL-L)
I = P ÷ (√3 x VL-L x Cosθ)
Conversion with Line to Neutral Voltage (VL-N)
I = P ÷ (3 x VL-N x Cosθ)
Where:
- P = Power in watts
- V = Voltage in volts
- I = Current in amperes
- Cosθ = Power factor in AC circuits
- VL-L = Line to Line Voltage in 3-Phase Circuits
- VL-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:
- 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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