kW to kVA to Amps Calculator (Single & Three Phase)

MEPbase Staff — Sat, 27 Jun 2026 06:27:14 +0000

Power triangle: PF = cos φ = kW ÷ kVA

Converting between kW, kVA and Amps is one of the most common tasks in electrical and HVAC engineering — whether you are sizing a cable, selecting a circuit breaker, or finding the full-load current of a generator or transformer. The converter below gives instant results for single phase and three phase systems, followed by all the formulas, solved examples, and a ready 415V quick reference chart.

kW / kVA / Amps Converter

System

I am entering

Value

Voltage (V)

Power Factor

Quick V:

Three-phase uses line-to-line voltage. Apply local code (NEC/IEC) derating for actual cable & breaker sizing.

kW vs kVA vs Amps — the basic difference

Before converting, it helps to understand what each term means:

kWReal power — the power that does actual work, such as running a motor or producing heat.

kVAApparent power — the total power the supply must deliver (real + reactive).

AmpsCurrent — what actually flows through the conductor and decides cable and breaker sizing.

The link between all three is the power factor (PF). This is the single most important relationship to remember:

kW = kVA × PF
|
kVA = kW ÷ PF

kW to kVA to Amps formulas

Three-phase formulas

Here V = line-to-line voltage (e.g. 400V / 415V / 480V), √3 = 1.732, and PF = power factor.

kVA → AmpsI = (kVA × 1000) ÷ (√3 × V)

kW → AmpsI = (kW × 1000) ÷ (√3 × V × PF)

Amps → kVAkVA = (√3 × V × I) ÷ 1000

Amps → kWkW = (√3 × V × I × PF) ÷ 1000

Single-phase formulas

kVA → AmpsI = (kVA × 1000) ÷ V

kW → AmpsI = (kW × 1000) ÷ (V × PF)

Amps → kVAkVA = (V × I) ÷ 1000

Amps → kWkW = (V × I × PF) ÷ 1000

DC formulas

DC systems have no power factor and no kVA:

PowerkW = (V × I) ÷ 1000

CurrentI = (kW × 1000) ÷ V

How to convert kW to Amps (step by step)

Select the system type — single phase or three phase.
Enter the voltage (line-to-line for three phase, e.g. 415V).
Enter the power factor (typically 0.8 for motor/mixed loads; 1 for purely resistive loads).
Apply the formula I = (kW × 1000) ÷ (√3 × V × PF).
Add the appropriate safety / derating factor before finalizing cable and breaker sizes.

Solved examples

Example 1 — kW to Amps (three-phase)

100 kW load at 415V, power factor 0.8.

I = (100 × 1000) ÷ (1.732 × 415 × 0.8) = 100000 ÷ 575.0

I = 173.9 A

Example 2 — kVA to Amps (three-phase)

200 kVA transformer / generator at 415V.

I = (200 × 1000) ÷ (1.732 × 415) = 200000 ÷ 718.8

I = 278.3 A

Power factor is not used here because kVA is already apparent power.

Example 3 — kW to Amps (single-phase)

5 kW load at 230V, power factor 0.9.

I = (5 × 1000) ÷ (230 × 0.9) = 5000 ÷ 207

I = 24.2 A

Example 4 — kW to kVA

80 kW load running at 0.8 power factor.

kVA = kW ÷ PF = 80 ÷ 0.8

kVA = 100 kVA

Quick reference chart (415V, three-phase, PF = 0.8)

Power (kW)	Apparent (kVA)	Current (Amps)
1	1.25	1.7
5	6.25	8.7
7.5	9.4	13.0
10	12.5	17.4
15	18.75	26.1
20	25	34.8
25	31.25	43.5
30	37.5	52.2
40	50	69.6
50	62.5	87.0
75	93.75	130.4
100	125	173.9
150	187.5	260.9
200	250	347.8
250	312.5	434.8
300	375	521.7
500	625	869.6

kVA to Amps chart (415V, three-phase)

Often searched separately for transformer and generator sizing (independent of power factor):

Rating (kVA)	Current (Amps)
10	13.9
25	34.8
50	69.6
100	139.1
200	278.3
250	347.8
315	438.2
500	695.7
630	876.6
1000	1391.3

These values are at 415V and 0.8 PF; for other voltages or power factors, use the calculator above.

How power factor affects the result

The lower the power factor, the higher the current for the same kW — meaning thicker cables and a larger breaker. This is why power-factor correction matters. Common defaults:

1.0Purely resistive loads (heaters, incandescent lighting).

0.8Typical mixed / motor loads — the usual design default.

0.6–0.7Lightly loaded motors or poor power-factor systems.

HP to kW and Amps

Motor ratings are often given in HP, so these conversions are handy:

HP → kWkW = HP × 0.746

kW → HPHP = kW ÷ 0.746

Use 0.736 for metric HP. Then apply the kW → Amps formula above to find the current.

Common voltage reference

System	Typical Voltage
Single phase	120V / 230V / 240V
Three phase (LV)	400V / 415V / 480V

Frequently Asked Questions

How many amps is 1 kVA at 415V three phase?

1 kVA ≈ 1.39 A at 415V three phase. Formula: I = (1 × 1000) ÷ (1.732 × 415) = 1.39 A.

Is kW the same as kVA?

No. kW is real power and kVA is apparent power, related by kW = kVA × power factor. They are equal only when the power factor is 1.

What is the kW to amps formula for three phase?

I = (kW × 1000) ÷ (√3 × V × PF), where V is the line-to-line voltage.

How many amps is 100 kW at 415V?

At 0.8 PF, 100 kW ≈ 173.9 A at 415V three phase.

How do I convert kW to kVA?

kVA = kW ÷ power factor. Example: 80 kW at 0.8 PF = 100 kVA.

Conclusion

Converting between kW, kVA and Amps is a basic step in every electrical design — from cable sizing to breaker and transformer selection. The converter above gives instant, standard-based results, and the formulas and charts let you verify them by hand. Always apply the derating and safety factors required by your local code (NEC / IEC) when finalizing a design.

Disclaimer: This tool is for reference only. Final electrical design should be verified by a qualified engineer in accordance with applicable standards (NEC / IEC 60038 / IEEE).

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