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kVA to Amps Conversion for Generators

Generator spec sheets list output in kVA (kilovolt-amperes), but breakers, wiring, transfer switches, and load calculations all work in amps. Converting between the two is essential for sizing a generator correctly, and the formula changes depending on whether you’re running single-phase or three-phase power.

Below you’ll find the formulas, worked examples, and quick-reference charts for the most common generator voltages. If your spec sheet lists kilowatts instead, see our guide on converting kW to amps for generators.

kVA to Amps Formulas

Single-phase:

Amps = (kVA × 1,000) ÷ Voltage

Three-phase:

Amps = (kVA × 1,000) ÷ (Voltage × 1.732)

The 1.732 in the three-phase formula is the square root of 3 (√3), which accounts for power being delivered across three conductors. Use the line-to-line voltage (e.g., 208V, 480V) in the three-phase formula.

Worked Examples

Example 1 — 50 kVA single-phase at 240V:
Amps = (50 × 1,000) ÷ 240 = 208.3 amps

Example 2 — 150 kVA three-phase at 480V:
Amps = (150 × 1,000) ÷ (480 × 1.732) = 150,000 ÷ 831.4 = 180.4 amps

Example 3 — going the other way (amps to kVA), 400A service at 208V three-phase:
kVA = (400 × 208 × 1.732) ÷ 1,000 = 144.1 kVA — so you’d look at a 150 kVA generator at minimum, and larger once headroom is factored in.

kVA to Amps Chart: Single-Phase Generators

Common single-phase voltages in North America are 120V and 240V.

Generator Size (kVA)	Amps at 120V	Amps at 240V
5	41.7	20.8
10	83.3	41.7
15	125.0	62.5
20	166.7	83.3
25	208.3	104.2
30	250.0	125.0
40	333.3	166.7
50	416.7	208.3
60	500.0	250.0
75	625.0	312.5
100	833.3	416.7
125	1,041.7	520.8
150	1,250.0	625.0
200	1,666.7	833.3
250	2,083.3	1,041.7
300	2,500.0	1,250.0
400	3,333.3	1,666.7
500	4,166.7	2,083.3
625	5,208.3	2,604.2
750	6,250.0	3,125.0
1000	8,333.3	4,166.7

kVA to Amps Chart: Three-Phase Generators

Three-phase is standard for commercial and industrial generators. Values below use line-to-line voltage and √3 = 1.732.

Generator Size (kVA)	Amps at 208V	Amps at 240V	Amps at 480V
5	13.9	12.0	6.0
10	27.8	24.1	12.0
15	41.6	36.1	18.0
20	55.5	48.1	24.1
25	69.4	60.1	30.1
30	83.3	72.2	36.1
40	111.0	96.2	48.1
50	138.8	120.3	60.1
60	166.5	144.3	72.2
75	208.2	180.4	90.2
100	277.6	240.6	120.3
125	347.0	300.7	150.4
150	416.4	360.8	180.4
200	555.1	481.1	240.6
250	693.9	601.4	300.7
300	832.7	721.7	360.8
400	1,110.3	962.3	481.1
500	1,387.9	1,202.8	601.4
625	1,734.8	1,503.5	751.8
750	2,081.8	1,804.2	902.1
1000	2,775.7	2,405.6	1,202.8

kVA vs. kW: What's the Difference?

kVA is apparent power; kW is real power. The two are linked by the power factor (PF):

kW = kVA × Power Factor

Most diesel generators are rated at a 0.8 power factor, so a 100 kVA generator delivers about 80 kW of usable power. Resistive loads like heaters run near PF 1.0, while motors and compressors typically run at 0.8–0.9. When a spec sheet gives you kW instead of kVA, use our kW to amps conversion guide.

Why This Matters When Sizing a Generator

Getting the kVA-to-amps conversion right protects you on both ends:

Undersizing trips breakers, stalls motor starts, and can damage both the generator and connected equipment. Oversizing wastes capital and causes wet stacking in diesel engines that run at light load for long periods.

A good rule of thumb is to calculate your total running amps, account for motor starting inrush (often 2–3× running current), then add 20–25% headroom. If you’d like help selecting the right unit, contact our team — we size generators for residential, commercial, and industrial applications every day.

Frequently Asked Questions

How many amps is a 100 kVA generator?

A 100 kVA three-phase generator delivers about 277.6 amps at 208V, 240.6 amps at 240V, or 120.3 amps at 480V. On single-phase 240V it would deliver about 416.7 amps.

What is the formula to convert kVA to amps?

For single-phase: Amps = (kVA × 1,000) ÷ Voltage. For three-phase: Amps = (kVA × 1,000) ÷ (Voltage × 1.732), where 1.732 is the square root of 3.

Is kVA the same as kW?

No. kVA is apparent power and kW is real power. They are related by the power factor: kW = kVA × power factor. Most generators are rated at a 0.8 power factor, so a 100 kVA generator provides about 80 kW.

Why are generators rated in kVA instead of kW?

kVA describes the total electrical output regardless of the load’s power factor. Since the generator manufacturer can’t know what power factor your equipment will run at, kVA is the universal rating; kW depends on your specific load.

How many kVA do I need to run 200 amps at 480V three-phase?

kVA = (Amps × Volts × 1.732) ÷ 1,000 = (200 × 480 × 1.732) ÷ 1,000 ≈ 166 kVA. Add 20–25% headroom and you’d typically select a 200 kVA unit.

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