Three-Phase Apparent Power
Also known as FLA from kVA · transformer full-load current · transformer secondary amps · rated current · kVA to amps · nameplate current
Worked example: 208 V, 50 A → 18.01 kVA — press Try an example to run it live, then adjust anything.
Enter your known values, leave one input blank, and solves for the missing one. Tap a variable’s symbol to see what it means, with a typical value. Try different units for next level excitement!
Three-phase power →
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Three-Phase Apparent Power explained
Apparent power is the product the copper actually feels: every amp heats the conductor whether or not it is in phase with the voltage. Volt-amperes and watts have identical dimensions — this solver's watt fields double as volt-amperes, and kW as kVA — but tradition keeps the names separate to remind you that S ≥ P always. A 208 V panel drawing 50 A per line is handling 1.732 × 208 × 50 ≈ 18 kVA regardless of what the loads are doing.
This is the number on a transformer's nameplate, and the reason it is: the transformer's limits are its winding heat (amps) and its core saturation (volts), neither of which knows anything about power factor. To size a service, work in kVA; to size a bill or a generator's engine, work in kW. Drop the √3 for single-phase and the formula is just S = VI.
Three-Phase Apparent Power formula
- = Apparent power (VA) (W)
- = Line-to-line voltage (V)
- = Line current (A)
Missing one of these? Work it out first, then come back
- Apparent power (VA) — Power Factor from Real and Apparent Power, Reactive Power (Power Triangle)
- Line-to-line voltage — Three-Phase Real Power, Single-Phase Real Power with Power Factor
- Line current — Available Short-Circuit Current from Percent Impedance, Transformer Full-Load Current