Amps to kVA Calculator
Convert amps to kVA for single-phase and three-phase systems, or work backwards from a kVA rating to the current it draws. WattSimple also names the next standard transformer size up and the real kW the load delivers at your power factor.
kVA is apparent power: volts × amps, before power factor. It is what conductors and transformer windings actually carry, which is why transformers and generators are rated in kVA rather than kW. Power factor only affects how much of that becomes useful work.
Apparent power
83.14 kVA
- Current
- 100 A
- Apparent power
- 83.14 kVA
- Real power @ 0.85 PF
- 70.67 kW
- Configuration
- 480 V 3ø
Next standard transformer size
112.5 kVA three-phase, leaving 26% spare capacity above the 83.14 kVA calculated.
Standard ratings only. Actual selection also accounts for future load growth, ambient and altitude derating, harmonic K-factor, and NEC 450 overcurrent protection. Confirm with the engineer of record.
Measure the real amps and volts
The converter works from nameplate or assumed figures. A clamp meter reads the actual current on one conductor without breaking the circuit; clamped around a whole cord it reads close to zero. A multimeter reads the voltage at the receptacle or terminals. Opening a panel or a live box is work for someone qualified.
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Clamp meter
Fluke 323
Best for: Measuring what a hardwired circuit actually draws, even in a crowded panel
Multimeter
Fluke 117
Best for: Anyone who will do this more than once a year
Frequently asked questions
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Open converterkW ↔ kVA
Convert kW to kVA at any power factor, with the next standard generator and transformer size up, the rating you actually have to buy for the load.
Open converterWatts ↔ Amps
Convert watts to amps (or amps to watts) for DC, single-phase, and three-phase, plus the NEC wire and breaker the result needs.
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Sources & standards
This tool's methodology and data follow US standards and authoritative public datasets: