How do you convert kW to amps?

For DC: divide power in watts by voltage (I = P/V). For AC single-phase: divide by voltage times power factor (I = P/(V×PF)). For AC three-phase with line-to-line voltage: divide by √3 × voltage × power factor (I = P/(√3×V×PF)). For example, 5 kW at 230V single-phase with PF 0.85: I = 5,000 / (230 × 0.85) = 25.6 amps.

How many amps is 1 kW?

It depends on voltage and power factor. At 230V single-phase with PF = 1: I = 1,000 / 230 = 4.35A. At 120V: I = 1,000 / 120 = 8.33A. At 400V three-phase with PF = 0.85: I = 1,000 / (1.732 × 400 × 0.85) = 1.70A. Higher voltage means less current for the same power.

How many amps is 5 kW?

At 230V single-phase with PF = 0.85: I = 5,000 / (230 × 0.85) = 25.6A. At 240V with PF = 1 (resistive load): I = 5,000 / 240 = 20.8A. At 480V three-phase with PF = 0.85: I = 5,000 / (1.732 × 480 × 0.85) = 7.07A. The answer always depends on voltage, circuit type, and power factor.

Why do I need to know the voltage to convert kW to amps?

Power (watts) equals voltage times current (P = V × I). Without knowing the voltage, you can't solve for current. The same 5 kW load draws 41.7A at 120V but only 10.4A at 480V. This is why industrial systems use higher voltages — it reduces current, allowing thinner wires and smaller breakers.

What is the kW to amps formula for 3 phase?

There are two formulas depending on the voltage measurement. Using line-to-line voltage: I = P(W) / (√3 × V_LL × PF). Using line-to-neutral voltage: I = P(W) / (3 × V_LN × PF). Both give the same result because V_LL = √3 × V_LN. For example, 400V line-to-line equals 231V line-to-neutral.

How does power factor affect the kW to amps conversion?

Lower power factor means higher current for the same kW. A 10 kW motor at PF 0.85 draws 51.2A at 230V (10,000 ÷ (230 × 0.85)), but at PF 0.60 it draws 72.5A (10,000 ÷ (230 × 0.60)) — about 42% more current. This extra current is reactive (doesn't do useful work) but still heats wires and trips breakers. Always size wires for the actual current, not just the kW rating.

What wire size do I need for a given kW load?

Convert kW to amps first, then apply the 125% rule for continuous loads. Use NEC Table 310.16: 14 AWG = 15A, 12 AWG = 20A, 10 AWG = 30A, 8 AWG = 40A, 6 AWG = 55A, 4 AWG = 70A (copper, 60°C). For runs over 30 meters, upsize one gauge to compensate for voltage drop. Always follow local codes.

Can I use this calculator for generator sizing?

Yes. If you know the total kW load, convert to amps to verify the generator's output rating is sufficient. Remember that generators are rated in kVA, not kW. A 10 kVA generator at PF 0.8 delivers only 8 kW of real power. Also add 20-25% margin for motor starting surges, which can draw 5-7× the running current for a few seconds.

kW to Amps Calculator

Power (P)

Voltage (V)

Power Factor (PF)

Current (AC Single-Phase)

25.58A

Current in All Units

Result converted to milliamps, amps, and kiloamps

25575.4

Milliamps

25.58

Amps

0.0256

Kiloamps

Apparent Power

Total power before power factor (S = V × I)

5.88

kVA

Apparent Power

Step-by-Step Solution

Calculation walkthrough with your values

1
Input Values
Conversion: kW → Amps (AC Single-Phase)
P = 5 kW = 5,000 W
V = 230 V = 230.0000 V
PF = 0.85
2
Result
I = P / (V × PF)
I = 5,000 / (230.0000 × 0.85)
I = 25.5754 A

How the kW to Amps Calculator Works

Find the current draw from a known power rating

This calculator converts kilowatts (power) to amps (current) by rearranging the fundamental power equation. Knowing the current draw is essential for selecting the right wire gauge, circuit breaker size, and ensuring your electrical panel can handle the load. The formula depends on the circuit type and, for AC circuits, the power factor.

DC Circuit

I(A) = P(W) / V

Direct current — no power factor

AC Single-Phase

I(A) = P(W) / (V × PF)

Residential & light commercial

AC 3-Phase (Line-to-Line)

I(A) = P(W) / (√3 × V_LL × PF)

Balanced load — line voltage measured

AC 3-Phase (Line-to-Neutral)

I(A) = P(W) / (3 × V_LN × PF)

Balanced load — phase voltage measured

Worked Example — 5 kW at 230V Single-Phase, PF = 0.85

Power

Voltage

230

Power Factor

0.85

Result

25.6

Why Convert kW to Amps?

Practical applications for electricians and engineers

Equipment is rated in kilowatts (power consumption), but wires, breakers, and panels are rated in amps (current capacity). Converting kW to amps bridges this gap — you need the current draw to select the right wire gauge, breaker size, and verify panel capacity.

Key Relationships

I = P / V — current equals power divided by voltage (DC)

I = P / (V × PF) — AC current includes power factor in denominator

Lower PF → Higher amps — poor PF means more current for same power

Higher voltage → Lower amps — why industrial systems use 480V instead of 120V

This calculator also supports the reverse conversion (amps → kW). Switch direction using the toggle at the top of the input panel.

Complete Formula Reference

kW to amps and amps to kW for every circuit type

Circuit	kW → Amps	Amps → kW
DC	I = P × 1000 / V	P = V × I / 1000
AC 1-Phase	I = P × 1000 / (V × PF)	P = V × I × PF / 1000
AC 3-Phase (V_LL)	I = P × 1000 / (√3 × V × PF)	P = √3 × V × I × PF / 1000
AC 3-Phase (V_LN)	I = P × 1000 / (3 × V × PF)	P = 3 × V × I × PF / 1000

Key Considerations

Important factors when sizing circuits from kW ratings

Apply the 125% Rule

NEC Article 210.19 requires conductors for continuous loads (3+ hours) to be rated at 125% of the load current. A 40A continuous load needs wire rated for 50A. This calculator shows the raw current — multiply by 1.25 for wire sizing.

Power Factor Increases Current

A motor rated 5 kW at PF 0.85 draws 25.6A, but the same motor at PF 0.60 draws 36.2A — 41% more current for the same power output. Always use the actual PF, not an assumed value.

Three-Phase Assumes Balanced Loads

The √3 and 3× formulas assume all three phases carry equal current. For unbalanced loads, measure each phase individually and sum P₁ + P₂ + P₃. Using one phase's current can over- or under-estimate total power.

Voltage Drop Over Distance

Long cable runs increase resistance, causing voltage drop at the load. If the actual voltage at the motor is lower than nominal, the current will be higher than calculated. For runs over 30m, upsize the wire gauge.

Quick Wire Sizing Reference

Copper conductor ampacity at 60°C (NEC Table 310.16)

AWG	Max Amps	Typical Use
14 AWG	15A	Lighting circuits
12 AWG	20A	General outlets
10 AWG	30A	Dryers, water heaters
8 AWG	40A	Ranges, large appliances
6 AWG	55A	Sub-panels, large motors
4 AWG	70A	Service entrance
2 AWG	95A	Large service entrance

Frequently Asked Questions

Common questions and detailed answers

First convert kW to amps using this calculator. Then apply the NEC 125% rule for continuous loads (3+ hours): multiply the calculated amps by 1.25. Select the next standard breaker rating per NEC 240.6(A) that meets or exceeds this value. Standard ratings include 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100A and more. Always consult local electrical codes — breaker sizing depends on conductor type, ambient temperature, and installation method.

kW (kilowatts) is real power — the actual power doing useful work. kVA (kilovolt-amperes) is apparent power — voltage times current without considering power factor. The relationship is kW = kVA × PF. For single-phase, current from kVA is I = kVA × 1000 / V. For three-phase (line-to-line), it's I = kVA × 1000 / (√3 × V). Generators and transformers are rated in kVA because they must handle the full apparent current regardless of PF.

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Last updated Apr 22, 2026

kW to Amps Calculator

Current in All Units

Apparent Power

Step-by-Step Solution

How the kW to Amps Calculator Works

Why Convert kW to Amps?

Complete Formula Reference

Key Considerations

Quick Wire Sizing Reference

Frequently Asked Questions

Embed kW to Amps Calculator

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