What this calculator actually models
Current depends on both power and voltage. AC loads can also depend on power factor, and balanced three-phase current uses the square-root-of-three factor when line-to-line voltage is entered.
How to use this calculator
Choose DC, single-phase AC or balanced three-phase AC.
Enter real power in watts and voltage in volts. For three-phase, use line-to-line voltage.
For AC, enter the load power factor between 0 and 1 and review the calculated current.
Where people use it
- •Equipment and power-supply sanity checks
- •Comparing current at different supply voltages
- •Electrical training and early-stage load calculations
Example: 1500 W at 120 V DC/resistive
1500 ÷ 120 = 12.5 A. For AC loads with a power factor below 1, the calculated current is higher.
Assumptions and limits
- •The result is a calculation, not a breaker, cable or code-compliance recommendation.
- •Three-phase mode assumes a balanced load and line-to-line voltage. Real installations can require efficiency, demand, harmonic and code considerations.
Frequently asked questions
How do I convert watts to amps?+
For DC or a unity-power-factor single-phase load, divide watts by volts.
Why is power factor included?+
For AC loads, real power can be lower than apparent power, so current depends on power factor.
What voltage should I enter for three-phase?+
This calculator uses line-to-line voltage in the balanced three-phase formula.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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