kVA to Amps Calculator
Enter power as kVA, kW or hp and get the current for single or three-phase, with the kW/kVA conversion made explicit and the formulas documented.
Open calculatorLast updated: 2026-09-15
How the calculation works
- kVA input is used directly; kW and hp are first converted to kVA through the power factor (hp at 746 W each).
- Single-phase divides kVA by voltage; three-phase divides by √3 times voltage.
- The result also shows real and apparent power so the PF conversion is visible.
Worked example
Interpreting the result
The result is the line current a balanced load draws at steady state. Use it for breaker sizing (with the applicable code multipliers), transformer loading checks and generator sizing. For motors, prefer nameplate FLA or NEC tables — the conversion here assumes the entered power is the electrical input.
Assumptions
- Balanced three-phase load, sinusoidal conditions.
- hp values are mechanical output power converted at 746 W per hp with the entered power factor.
Limitations
- Does not include motor inrush, harmonics or unbalance.
- Transformers are sized by kVA, but their actual loading also depends on the load's power factor.
kVA is what the wire carries — kW is what the load does
Every conversion on this page runs through the power triangle: kW (real work) and kVAR (reactive exchange) combine into kVA (apparent power), and only kVA sets the current. That is why a 10 kW load at PF 0.75 draws 13.3 kVA — a third more current for the same useful work. Transformers and generators are rated in kVA precisely because they must carry the whole triangle without knowing the load's power factor in advance.
Where the √3 comes from
In a balanced three-phase system the three line currents are displaced 120°, and summing their vector contributions produces the factor √3 (≈1.732) between line-to-line voltage and phase quantities. The practical consequence: at the same kVA and the same conductor current per line, a three-phase system at 400 V delivers 1.73× the power of a single-phase system at 230 V — the reason everything above a few kW is wired three-phase.
Frequently asked questions
How many amps is 10 kVA at 240 V single-phase?
10,000 / 240 = 41.7 A. At 480 V three-phase it would be 1000 / (1.732 × 480) = 12.0 A.
Why does power factor matter?
kW is the real work; kVA is what the wires must carry. At PF 0.8, delivering 8 kW requires 10 kVA of current capacity. Low PF therefore increases conductor and breaker sizes for the same useful power.