Amps to Watts Calculator & Conversion – DC/AC (1 & 3 Phase)
How to Convert Amperes (A) to Watts (W)? Simple and Advanced Calculators
You can use the following two calculators (Simple and Advance) to calculate the electric power in watts from electric current in amperes and electric voltage in volts.
In Simple Amps to Watt calculator, you can calculate any value of Power in Watts, Current in Amperes and Voltage in Volts by entering any two known values for P, V or I.
In Advanced Amps to Watts Calculator, you can calculate the electric power in watts, milliwatts or kilowatts from electric current in amperes, milliamperes and kiloamperes and RMS voltage in volts for DC circuits, AC 1-Phase Circuits and AC 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 and Delta Connections – Comparison Of Y/Δ.
Note 1: If you are on mobile phones, click on the “…” dotes beside the “Advanced Calculator” to select another simple calculator. For better experience through mobile phones, use the calculator in landscape position.
Note 2: For higher values like, 3×103, 5×10-6, 1.5 x1012, enter the value like this for scientific notation as 3e3, 5e-6, 1.5e12 etc.
DC Current in AMP to Watt Conversion
P = V x I
AC Single Phase Current in AMP to Watt Conversion
P = V x I x Cosθ
AC Three Phase Current in AMP to Watt Conversion
Conversion with Line to Line Voltage (VL-L)
P = √3 x VL-L x I x Cosθ
Conversion with Line to Neutral Voltage (VL-N)
P = 3 x VL-N x I 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 Amps to Watts?
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.
Power (P) in Watts = Voltage (V) in Volts x Current (I) in Amps
P = V x I
If we put the values of V and I in the above equations from Ohm’s law, we mat get the power as follow as well.
P = I2 x R
P = V2 ÷ R
Examples:
- 120V x 10A = 1200 W
- 230V x 5A = 1150 W
- 12V x 3A = 36 W
Equivalent Amps and Watts at 120V AC, 230V AC and 12V DC
The following table shows the different values of Wattage for 120V and 230V AC and 12V DC at unity power factor “1”.
| Voltage in Volts | Current in Amp | Power in Watts |
| 120V AC |
1 |
120 W |
| 230V AC | 230 W | |
| 12V DC | 12 W | |
| 120V AC |
5 |
600 W |
| 230V AC | 1150 W | |
| 12V DC | 60 W | |
| 120V AC |
10 |
1200 W |
| 230V AC | 2300 W | |
| 12V DC | 120 W | |
| 120V AC |
15 |
1800 W |
| 230V AC | 3450 W | |
| 12V DC | 180 W | |
| 120V AC |
20 |
2400 W |
| 230V AC | 4600 W | |
| 12V DC | 240 W | |
| 120V AC |
30 |
3600 W |
| 230V AC | 6900 W | |
| 12V DC | 360 W | |
| 120V AC | 50 |
6000 W |
| 230V AC | 11500 W | |
| 12V DC | 600 W | |
| 120V AC |
70 |
8400 W |
| 230V AC | 16100 W | |
| 12V DC | 840 W | |
| 120V AC |
100 |
12000 W |
| 230V AC | 23000 W | |
| 12V DC | 1200 W |
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