How Many Amps Is 3 kVA at 100V?

A 3 kVA single-phase load at 100V draws 30 amps. Three-phase configurations are not typical at this voltage. At a load power factor of 0.8 the load's real-power draw is 2.4 kW (a generator or UPS feeding this load has a separate kW rating set by the manufacturer which must be checked independently against the kVA rating).

3 kVA equals 30 amps at 100 volts (single-phase)

30 Amps

Try: 2kVA at 100V 1kVA at 100V 5kVA at 100V 7.5kVA at 100V

kVA

Volts

Amps (1Φ)

Assumes a single-phase AC circuit at the input voltage. kVA is apparent power, so no power factor term is involved.

Formulas

Single Phase

I_(A) = (kVA × 1000) ÷ V

(3 × 1000) ÷ 100 = 3,000 ÷ 100 = 30 A

Generator & UPS Sizing

Load-Side Real Power by Power Factor

A load with an apparent power of 3 kVA draws different amounts of real power depending on the load's own power factor. The table below is a load-side conversion, not a forecast of what a generator or UPS will output for that load: generators and UPS units publish their own independent kW rating set by the engine or inverter design, and that rating is often lower than kVA × the load's PF.

Load Type	Load PF	Load Real Power (kW)	Current at 100V
Resistive (heaters, lights)	1.0	3 kW	30 A
Mixed typical	0.85	2.55 kW	30 A
Motors/HVAC	0.80	2.4 kW	30 A
Computers/servers (no PFC)	0.65	1.95 kW	30 A

Note: current draw stays the same across the rows because kVA sets the current, not the load's power factor. PF only affects how much real work (kW) the load does per amp drawn.

Sizing a load against a source. If you are feeding this load from a UPS, generator, or transformer, check the load against both the source's kVA rating AND the source's kW rating. Those are two independent numbers published by the manufacturer. A 10 kVA / 8 kW generator, for example, can supply up to 10 kVA of apparent power AND up to 8 kW of real power, whichever limit is reached first. Do not use the kW figures above as a substitute for the source's published kW rating.

Circuit Sizing: Starting Points

The numbers below are rough order-of-magnitude starting points under typical assumptions (copper conductors, 75°C terminations, short run, no ambient or bundling derates, non-continuous duty). They are not install specs. Actual breaker and wire selection depends on the equipment nameplate, conductor and termination temperature ratings, cable type, run length and voltage-drop target, ambient and bundling conditions, whether the load is continuous, any NEC 430/440 motor or HVAC provisions, and local code.

	Single Phase
Current draw (at full kVA)	30 A
Ballpark branch OCP	~30A

For a real install, run the full wire-size calculator with your actual run length, voltage, and drop target, and verify breaker selection against the equipment nameplate and local code.

Energy Cost at Full Load

A load with an apparent power of 3 kVA at load PF 0.85 draws 2.55 kW of real power. Running cost at that draw: $0.43/hour at $0.17/kWh (rates last reviewed April 2026), or $104.04/month (8h/day). Full breakdown.

kW Equivalent

3 kVA at PF 0.85 = 2.55 kW. See 2.55 kW to amps at 100V.

Other kVA Ratings at 100V

kVA	Single Phase Amps	Real Power (PF 0.8)
1 kVA	10 A	0.8 kW
2 kVA	20 A	1.6 kW
3 kVA	30 A	2.4 kW
5 kVA	50 A	4 kW
7.5 kVA	75 A	6 kW
10 kVA	100 A	8 kW
15 kVA	150 A	12 kW
20 kVA	200 A	16 kW
25 kVA	250 A	20 kW
30 kVA	300 A	24 kW
40 kVA	400 A	32 kW
50 kVA	500 A	40 kW

Frequently Asked Questions

How many amps is 3 kVA at 100V?expand_more

3 kVA at 100V is 30 amps (single-phase). 100V is a single-phase voltage; three-phase configurations are not typical at this voltage.

Why are UPS and generators rated in kVA not 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. UPS and generator manufacturers publish a separate kW rating in addition to the kVA rating, set by the inverter or engine design, and it 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: the two ratings are independent specs and a load has to fit under each of them when sizing against the source.

What is the difference between kVA and kW?expand_more

kVA is apparent power (V×I), which sets the current on the circuit and the sizing of conductors, breakers, and windings. kW is real power (the portion that does useful work), equal to kVA×load PF. A load with an apparent power of 3 kVA at load PF 0.8 draws 2.4 kW of real power. For a source such as a generator or UPS, kVA and kW are two independent manufacturer ratings, not two views of the same spec, and both have to be checked when sizing a load.

What size breaker would I need for 3 kVA at 100V?expand_more

This is a sizing question, not a conversion question, and there is no single answer from a page like this. Breaker selection depends on the equipment nameplate FLA, whether the load is continuous (NEC 210.19(A) applies the 125% continuous-load rule), conductor ampacity and termination temperature, any NEC 430/440 motor or HVAC provisions, and local code. The current draw on this page is the input to that sizing process, not the output. Verify against the equipment nameplate and a licensed electrician.

Can a 3 kVA generator run my whole house?expand_more

A 3 kVA unit typically covers essentials (refrigerator, lights, phone and laptop chargers, a furnace blower) but not central AC, electric resistance heat, or an electric range running at the same time. Real capacity depends on simultaneous load, motor starting current, and manual or automatic load shedding.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.