kVA to Amps Calculator - Single-Phase and Three-Phase Current

Agarapu Ramesh — Editor and content reviewer
Editorially reviewed Reviewed by Agarapu Ramesh, science educator (chemistry). LinkedIn
Last reviewed: May 2026 | Standard electrical engineering formulas

kVA tells you apparent power. To get amps, divide by voltage. For three-phase, divide by sqrt(3) x line voltage. This is one of the first checks before choosing cable, breaker or transformer terminals.

Formula at a glance

  • single-phase: A = kVA x 1000 / V
  • three-phase: A = kVA x 1000 / (1.732 x V)
  • VA = kVA x 1000

Field note: Do not size the cable from the rounded catalog kVA alone. Voltage, phase, ambient temperature and installation method all still matter.

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Calculator Tool

Convert kilovolt-amperes to amperes

kVA
V
Result
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Formulas

1φI = (kVA × 1000) / V
3φI = (kVA × 1000) / (√3 × V)

Quick Reference

kVA @240V 1φ @480V 3φ
25 104 A 30 A
50 208 A 60 A
100 417 A 120 A
500 2083 A 601 A
1000 4167 A 1203 A

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How to use the kVA to Amps Calculator

Use this as a fast electrical check, then compare the result with the nameplate, measured voltage and power factor. The formula is clean. Real panels, motors and UPS loads usually have one extra wrinkle.

Worked example

Example: 25 kVA at 240 V single-phase is 104.2 A. A 25 kVA transformer at 415 V three-phase is 34.8 A per line.

Practical checks before you trust the number

  • Use line-to-line voltage for three-phase.
  • kVA is apparent power, so power factor is not part of this amp formula.
  • Add code margin and derating before selecting a real conductor.

Common mistake

Do not size the cable from the rounded catalog kVA alone. Voltage, phase, ambient temperature and installation method all still matter.

Sources and references

Related calculators

Frequently Asked Questions

For single-phase, use kVA x 1000 / volts. For 3-phase, divide by 1.732 times line voltage.

No. kVA is apparent power, so PF is not used for this current conversion.

The power is shared across three phases, so current per phase is lower for the same kVA and voltage range.

It gives running current, but final cable sizing must consider code, temperature, distance, voltage drop and protection.