Current Calculator – AC and DC (Volts, Watts, Ohms, Power Factor)
Calculate AC/DC current in amps from voltage, power (watts/kW), power factor, or resistance. Supports single-phase, three-phase, and Ohm’s Law.
Supports:
- Single-phase and three-phase systems
- Active power → current
- Apparent power → current
- Resistance/impedance → current
- Bilingual support
Key Formulas
Three-phase: I = P / (√3 × V × cosφ)
Single-phase: I = S / V
Three-phase: I = S / (√3 × V)
Single-phase: I = V / R
Three-phase: I = V / (√3 × Z)
Example
→ Current ≈ 17.5 A
Typical Equipment Current Reference
| Equipment | Power | Voltage | Power Factor | Estimated Current |
|---|---|---|---|---|
| Household Refrigerator | 150 W | 230 V | 0.95 | ≈ 0.69 A |
| LED Lighting (Total Load) | 200 W | 230 V | 0.98 | ≈ 0.89 A |
| Electric Kettle | 2.2 kW | 230 V | 1.0 | ≈ 9.6 A |
| Air Conditioner (1.5 HP) | 1.1 kW | 230 V | 0.85 | ≈ 5.6 A |
| Three-Phase Water Pump | 7.5 kW | 400 V | 0.88 | ≈ 12.3 A |
| Industrial Motor (15 kW) | 15 kW | 400 V | 0.9 | ≈ 24.1 A |
| Solar Inverter (DC Output) | 5 kW | 48 V | — | ≈ 104 A |
Frequently Asked Questions (FAQ)
Can this calculator handle both AC and DC circuits?Yes! It supports DC (using I = P/V or I = V/R) and AC single-phase/three-phase systems (with power factor and impedance).
What if I don’t know the power factor?For resistive loads (heaters, incandescent lamps), use PF = 1.0. For motors, a typical value is 0.8–0.9. You can adjust it to see how current changes.
Is this suitable for motor full-load current (FLC) estimation?This tool calculates theoretical current using formulas. For NEC-compliant FLC values, refer to standard tables—but this is excellent for preliminary sizing and understanding.
Why does three-phase current use √3 in the formula?In balanced three-phase systems, line voltage is √3 times the phase voltage, which reduces the current per conductor for the same power—improving efficiency.
Applications
- Home Electrical Projects: Size breakers, wiring, and outlets based on appliance current draw.
- Solar & Battery Systems: Calculate DC current for inverters, charge controllers, and battery banks.
- Industrial Maintenance: Estimate motor or pump operating current before installation.
- Education & Training: Visualize how voltage, power, and power factor affect current in real time.
- Energy Audits: Convert equipment nameplate data (kW, V, PF) into actual current for load analysis.
Who Should Use This Tool?
- Electrical engineers and designers
- Electricians and maintenance technicians
- Students of physics or electrical engineering
- DIY homeowners installing EV chargers, solar panels, or workshops
- Renewable energy professionals
