kVA to Amps Calculator

Convert kilovolt-amps to amps at any voltage for generators, UPS systems, transformers, and commercial distribution equipment. Supports single-phase and three-phase (both line-to-line and line-to-neutral) so the residential split-phase and commercial three-phase answers land side by side.

Apparent Power (kVA)

Voltage (Volts)

Phase

Voltage Reference

= 41.67 amps

See full breakdown for 10kVA at 240V

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What Is kVA?

kVA (kilovolt-amps) measures apparent power, the product of voltage and current in an AC circuit, which includes both real power (watts) and reactive power (VARs). The circuit's current draw, and therefore the sizing of conductors, breakers, and transformer windings, is set by the kVA figure regardless of the load's power factor. Generators, UPS systems, and distribution transformers publish a kVA rating for exactly this reason. They also publish a separate kW rating for the real-power side of the same hardware, and both ratings need to be checked independently when sizing a load against the source.

The Formulas

Single Phase

Amps = (kVA × 1000) ÷ Volts

Used for residential and light commercial UPS systems, small generators, and single-phase transformers. The 1000 factor converts kVA to VA before dividing by the line voltage.

Three Phase

Amps = (kVA × 1000) ÷ (Volts × √3)

Used for commercial generators, UPS systems, and distribution transformers at 208V, 240V, or 480V. Unlike kW-to-amps, this formula does not include power factor because kVA already represents the total apparent power. The current is the same regardless of whether the load is resistive or reactive.

kVA vs kW (Load-Side vs Source-Side)

For a load, kW is the real power the load consumes (kW = kVA × load PF), and kVA is the apparent power the load pulls from the circuit. The relationship kW = kVA × Power Factor is a load-side conversion: it tells you how much real power a load with a given apparent power and power factor is drawing.

For a generator, UPS, or transformer, kW and kVA are two independent ratings set by the manufacturer, not two views of the same spec. A nameplate "10 kVA / 8 kW" means the alternator and winding are rated for 10 kVA of apparent power and the prime mover (engine, inverter, or core) is rated for 8 kW of real power. The kW rating is set by the engine or inverter design, not by multiplying kVA times an assumed power factor. Connect a PF 1.0 resistive load to a 10 kVA / 8 kW generator and the output still caps at 8 kW because the engine is the limiter; connect a PF 0.6 load and the output caps at 6 kW because the alternator current is the limiter. Always size a load against both the source's kVA rating and its kW rating independently, and check the manufacturer's spec sheet rather than inferring one from the other.

Unlike kW-to-amps conversion, kVA-to-amps does not involve power factor in the arithmetic because kVA already includes both real and reactive power. The circuit math is straightforward: Amps = (kVA × 1000) ÷ Volts for single-phase, and Amps = (kVA × 1000) ÷ (Volts × √3) for three-phase line-to-line.

Quick Results Table

Each cell uses the primary interpretation for its voltage so the table lines up with the result pages: residential 120/240V as single-phase, 230V as single-phase, commercial 208/400/480V as three-phase L-L per line. Click any cell to open the full breakdown for that kVA/voltage combination.

kVA	120V 1Φ	208V 3Φ L-L	230V 1Φ	240V 1Φ	400V 3Φ L-L	480V 3Φ L-L
1 kVA	8.33A	2.78A	4.35A	4.17A	1.44A	1.2A
2 kVA	16.67A	5.55A	8.7A	8.33A	2.89A	2.41A
5 kVA	41.67A	13.88A	21.74A	20.83A	7.22A	6.01A
10 kVA	83.33A	27.76A	43.48A	41.67A	14.43A	12.03A
15 kVA	125A	41.64A	65.22A	62.5A	21.65A	18.04A
20 kVA	166.67A	55.51A	86.96A	83.33A	28.87A	24.06A
25 kVA	208.33A	69.39A	108.7A	104.17A	36.08A	30.07A
50 kVA	416.67A	138.79A	217.39A	208.33A	72.17A	60.14A
75 kVA	625A	208.18A	326.09A	312.5A	108.25A	90.21A
100 kVA	833.33A	277.57A	434.78A	416.67A	144.34A	120.28A

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Frequently Asked Questions

How do I convert kVA to amps?expand_more

Single-phase: Amps = (kVA × 1000) ÷ Volts. Three-phase (L-L): Amps = (kVA × 1000) ÷ (Volts × √3). Residential voltages (120/240V split-phase) are typically single-phase, so 10 kVA at 240V single-phase is about 41.67 amps. Commercial voltages (208/400/480V) are typically three-phase L-L, so 10 kVA at 208V three-phase is about 27.76 amps per line. Pick the formula that matches your actual system.

What is the difference between kVA and kW?expand_more

kVA is apparent power (voltage × current), which sets the circuit's current draw and sizes the conductors and breakers. kW is real power (the part that does useful work), equal to kVA × the load's power factor. A load with an apparent power of 10 kVA at PF 0.8 draws 8 kW of real power. kVA is always ≥ kW for the same load.

How do I size a generator in kVA?expand_more

Generator sizing is not a single-formula calculation. A rough napkin pass: add the steady-state watts of everything you plan to run, divide by a planning power factor (often 0.8, but not universal), convert to kVA, and add margin. Then cross-check against the generator's published kW rating, which is a separate manufacturer spec set by the engine (prime mover) and is not the same as kVA × design PF. The caveats that actually drive a real spec: motor and compressor inrush can be several times steady-state current, load diversity and sequencing affect peak demand, voltage-dip tolerance of sensitive equipment limits how much motor load a given genset can start, and altitude and ambient temperature both derate output. A 10 kW steady-state load at PF 0.8 maps to 12.5 kVA of apparent power on paper, but that number alone is not sufficient for a real installation, run a load calc and check the manufacturer spec for both ratings.

Why are UPS and generators rated in kVA instead of kW?expand_more

Because the current on the output (and therefore the conductor, switchgear, and winding sizing) is set by apparent power, kVA = V × I, regardless of the load's power factor. Manufacturers also publish a separate kW rating for the unit, set by the UPS inverter design or the generator's engine, which is often lower than the kVA rating. You cannot derive a UPS or generator's kW output from its kVA rating and the load's power factor: both ratings are independent manufacturer specs and the load has to fit under each.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician for electrical installations.

Standards & References

This page cites the following electrical codes and standards. Always consult the current edition of your local adopted standard for authoritative requirements.

NEC Table 310.16. Allowable ampacities of insulated conductors rated up to 2000V, 60°C through 90°C, not more than three current-carrying conductors in raceway or cable.
National Electrical Code (NFPA 70), Article 310, Conductors for General Wiring. Reference →
NEC Article 450. Transformers and transformer vaults: installation requirements, overcurrent protection, and ventilation for dry-type and liquid-filled transformers in the US.
National Electrical Code (NFPA 70). Reference →
IEC 60076. Power transformers: rating, construction, testing, and loading guidelines. International equivalent to IEEE C57 for oil-immersed and dry-type power transformers.
International Electrotechnical Commission. Reference →
IEC 60038. IEC standard voltages. Defines 230/400V as the nominal low-voltage supply for 50Hz systems, which harmonized European residential supply in 1995.
International Electrotechnical Commission. Reference →
ANSI C84.1. American National Standard for Electric Power Systems and Equipment: Voltage Ratings (60 Hz). Defines the nominal system voltages (120, 208, 240, 277, 480V) and their allowable ranges at the service entrance and utilization point.
American National Standards Institute / NEMA. Reference →

Disclaimer: The information on this page is provided for reference. Always consult a licensed electrician and the current edition of your local adopted electrical code before performing electrical work.