Amps to kVA Calculator
Use this free and accurate Amps to kVA Calculator to convert electrical current in Amperes (A) to apparent power in kilovolt-amperes (kVA) and volt-amperes (VA), real working power in kilowatts (kW), and reactive power (kVAR) for Single-Phase AC, 3-Phase AC (Line-to-Line & Line-to-Neutral), and Direct Current (DC) circuits.
| Real Power (kW): | 19.20 kW (19,200 W) |
| Reactive Power (kVAR): | 14.40 kVAR |
| Mechanical Equivalent: | 25.7 HP |
| NEC Circuit Breaker: | 125A Breaker |
| Min 75°C Wire (Cu): | 1 AWG Copper |
| 80% Safe Continuous: | 80.0 A (19.20 kVA) |
| Recommended Gen: | 30 kVA (24 kW) |
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Amps to kVA Calculation Formulas
Apparent power in kilovolt-amperes (kVA) represents the total electrical capacity demanded from an electrical source or generator. The exact formula depends on whether the system is Single-Phase AC, Three-Phase AC (Line-to-Line vs Line-to-Neutral), or Direct Current (DC):
1. Single-Phase AC:
Where I = Current in Amperes, V = RMS Voltage (e.g. 120V or 240V).
2. 3-Phase AC (Line-to-Line):
Where √3 ≈ 1.73205, I = Phase Current, VLL = Line-to-Line Voltage (e.g. 208V, 480V).
3. 3-Phase AC (Line-to-Neutral):
Where VLN is the line-to-neutral voltage (e.g. 120V on 208Y, 277V on 480Y).
4. Direct Current (DC):
In DC circuits with zero phase displacement, Power Factor is always 1.0 (kVA = kW).
Amps to kVA Conversion Reference Tables
Single-Phase AC Power Ratings:
| Current (A) | 120V | 208V | 240V |
|---|---|---|---|
| 15 A | 1.80 kVA | 3.12 kVA | 3.60 kVA |
| 20 A | 2.40 kVA | 4.16 kVA | 4.80 kVA |
| 30 A | 3.60 kVA | 6.24 kVA | 7.20 kVA |
| 50 A | 6.00 kVA | 10.40 kVA | 12.00 kVA |
| 100 A | 12.00 kVA | 20.80 kVA | 24.00 kVA |
| 200 A | 24.00 kVA | 41.60 kVA | 48.00 kVA |
3-Phase AC (Line-to-Line kVA):
| Current (A) | 208V | 480V | 600V |
|---|---|---|---|
| 20 A | 7.21 kVA | 16.63 kVA | 20.78 kVA |
| 50 A | 18.01 kVA | 41.57 kVA | 51.96 kVA |
| 100 A | 36.03 kVA | 83.14 kVA | 103.92 kVA |
| 200 A | 72.05 kVA | 166.28 kVA | 207.85 kVA |
| 400 A | 144.11 kVA | 332.55 kVA | 415.69 kVA |
| 800 A | 288.21 kVA | 665.11 kVA | 831.38 kVA |
Frequently Asked Questions (FAQ)
What is the difference between kVA and kW?
kVA (apparent power) is the total power flowing through conductors and transformers, while kW (active power) is the actual useful work done (mechanical movement, light, heat). They are related by Power Factor: kW = kVA × PF.
Why do generators and transformers rate in kVA instead of kW?
Conductors and magnetic cores heat up based on total current (Amperes) regardless of whether power factor is 1.0 or 0.8. Sizing in kVA ensures electrical windings remain within safe thermal limits regardless of inductive motor loads.
What is the NEC 80% continuous load rule?
According to the National Electrical Code (NEC Article 210.20), branch circuit overcurrent protective devices (circuit breakers) must not carry continuous loads running 3 hours or more exceeding 80% of their nameplate rating.