← All calculators
Ohm's law and power calculator
Volts, amps, ohms and watts, plus kW to amps for single and three-phase.
Ohm's law
Fill in any two. Leave the others blank.
- Voltage
- 230 V
- Current
- 10.435 A
- Resistance
- 22.042 Ω
- Power
- 2,400 W
Method
- I = P ÷ V
- then R = V ÷ I and P = V × I
Reference
- Ohm's law and the power equation
Notes
- For resistive loads. For motors and other AC loads, use power factor below.
Verify against the current standard before relying on this.
kW ↔ amps
- Current per phase
- 12.7 A
Method
- I = P ÷ (√3 × V × pf)
- = 7500 W ÷ (√3 × 400 V × 0.85) = 12.7 A
Reference
- Three-phase power: P = √3 × VL × IL × pf
Notes
- For motors, use the nameplate full-load current where you have it.
Verify against the current standard before relying on this.
Put the numbers straight into a quote
SparkyBuddy does the quoting, invoicing and certificates too. Free to start.