Kilowatts to Amps Calculator
Convert real power in kilowatts to current using the electrical system, voltage and power factor. The result is an arithmetic estimate, not a circuit-sizing decision.
Quick answerAt 230 V single-phase and power factor 1, 3 kW is 13.04 A. At 120 V it is 25 A. On a balanced 400 V three-phase system at power factor 0.8, 3 kW is 5.41 A.
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How it works
DC or single-phase amps = kW × 1,000 ÷ (volts × power factor). Balanced three-phase line amps = kW × 1,000 ÷ (√3 × line-to-line volts × power factor). Do not use the result alone to size wiring, breakers or protection.
Kilowatts to amps conversion chart
The first two columns are DC or single-phase at power factor 1. The final column is balanced three-phase at 400 V line-to-line and power factor 0.8.
| Real power | 120 V, 1-phase | 230 V, 1-phase | 400 V, 3-phase, PF 0.8 |
|---|---|---|---|
| 0.5 kW | 4.17 A | 2.17 A | 0.90 A |
| 1 kW | 8.33 A | 4.35 A | 1.80 A |
| 2 kW | 16.67 A | 8.70 A | 3.61 A |
| 3 kW | 25.00 A | 13.04 A | 5.41 A |
| 5 kW | 41.67 A | 21.74 A | 9.02 A |
| 10 kW | 83.33 A | 43.48 A | 18.04 A |
Balanced three-phase calculations do not describe phase imbalance, harmonics, startup current or transient demand. Use qualified electrical guidance for equipment and circuit decisions.
Worked example: 3 kW at 230 V single-phase
Multiply 3 kW by 1,000 to get 3,000 W. Divide by 230 V × power factor 1: 3,000 ÷ 230 = 13.04 A. At power factor 0.8, the same 3 kW of real power would require 3,000 ÷ (230 × 0.8) = 16.30 A.
The lower power factor increases current for the same real kW. Use a documented or measured value rather than assuming every AC load is 1.
Worked example: 3 kW on balanced three-phase
For 3 kW at 400 V line-to-line and power factor 0.8, divide 3,000 W by √3 × 400 V × 0.8. The result is about 5.41 A of line current for the balanced formula.
Do not enter line-to-neutral voltage into this line-to-line version. An unbalanced system requires phase-by-phase information rather than a single √3 shortcut.
Real kW, apparent power and power factor
This calculator begins with real power in kW. For AC loads, power factor relates real power to volts and amps; it is not an efficiency percentage. A motor drive, power supply or other nonlinear load can also introduce harmonics that a simple steady-state formula does not describe.
Use the same operating condition for kW, voltage and power factor. Mixing maximum nameplate kW with a part-load measured power factor can produce a misleading current.
Why this is not a breaker-sizing calculator
Circuit design must consider continuous-load rules, equipment nameplates, minimum circuit ampacity, maximum overcurrent protection, conductor temperature and installation method, starting current, local code and manufacturer instructions. This page calculates one operating-current relationship only.
Use a qualified electrician and the applicable code for wiring, breaker, disconnect, generator or inverter sizing.
Sources used for assumptions: Schneider Electric — single-phase and balanced three-phase power calculations; NIST — SI units of electric current and the relationship 1 V = 1 W/A; U.S. Energy Information Administration — watts, kilowatts and electricity measurement.
Frequently asked questions
How many amps is 3 kW at 230 V?
At power factor 1 on DC or single-phase AC, 3 kW is 13.04 A. At power factor 0.8 it is 16.30 A.
How many amps is 3 kW at 120 V?
At power factor 1 on DC or single-phase AC, 3 kW is 25 A.
Does this calculate three-phase current?
Yes, for a balanced system. Select three-phase and enter real total kW, line-to-line voltage and power factor. Unbalanced loads need phase-by-phase calculation or measurement.
Why does power factor change the answer?
For the same real kW and voltage, a lower power factor requires more current. Use a documented or measured AC power factor for the same operating condition.
Can I calculate amps from kW without voltage?
No. Current depends on voltage and, for AC, power factor and the electrical system.
Is kW the same as kVA?
No. kW is real power; kVA is apparent power. For a simple balanced relationship, kW = kVA × power factor.
Can I size a breaker or cable from this result?
No. Use equipment nameplates, manufacturer instructions, applicable electrical code and qualified guidance; this estimate omits several design requirements and transient conditions.
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