Wattage Amps Calculator
Calculate electrical power (watts) from current (amps) and voltage, or vice versa. Also supports DC and AC single-phase systems.
Published by:
isCalculator Editorial Team
Was this calculator helpful?
How to use this tool?
This calculator computes electrical values using Ohm’s Law and the power formula. Follow these steps:
- Select calculation type – Choose whether to calculate Watts (P), Amps (I), or Volts (V).
- Choose system type – Select DC or AC Single Phase. For AC, a Power Factor field appears (enter a value between 0 and 1, e.g., 0.8).
- Enter the required values – The calculator will enable only the fields needed for your chosen calculation:
- Calculate Watts: Enter Voltage (V) and Current (A).
- Calculate Amps: Enter Voltage (V) and Power (W).
- Calculate Volts: Enter Current (A) and Power (W).
- Click “Calculate” – The result appears immediately, showing the computed value and the formula used.
Note: All inputs accept decimal numbers. Ensure values are positive. The Power Factor is only required for AC calculations and must be between 0 and 1.
Previous Results
| Result | Inputs | Date |
|---|
Frequently Asked Questions
DC (Direct Current) uses the formula P = V × I, while AC (Alternating Current) single-phase uses P = V × I × PF, where PF is the power factor (0 to 1). For AC, you need to provide the power factor.
Select 'Calculate Amps' from the dropdown. Enter voltage and power (watts). For AC, also enter the power factor. The calculator will use I = P / V for DC or I = P / (V × PF) for AC.
Ensure all required inputs are valid numbers greater than zero. Avoid zero voltage or zero current when calculating watts. The calculator will display an error message for invalid inputs.