Amps to kVA Calculator
Convert amperes to kilovolt-amperes (apparent power) for DC, single-phase, and three-phase AC systems.
Result
Amps
10.00
A
Volts
120.00
V
Type
AC - Single phase
Apparent Power
1.2000 kVA
1,200.00 VA
Quick Reference
kVA vs kW
kVA is apparent power. kW is real power.
kW = kVA × Power Factor
For pure resistive loads (DC, heaters), kVA = kW. For motors and electronics with PF < 1, kVA > kW.
Amps to kVA Conversion Table
| Amps (A) | Volts (V) | Phase | kVA |
|---|---|---|---|
| 1 A | 120 V | Single-phase | 0.1200 kVA |
| 5 A | 120 V | Single-phase | 0.6000 kVA |
| 10 A | 120 V | Single-phase | 1.2000 kVA |
| 20 A | 120 V | Single-phase | 2.4000 kVA |
| 1 A | 240 V | Single-phase | 0.2400 kVA |
| 5 A | 240 V | Single-phase | 1.2000 kVA |
| 10 A | 240 V | Single-phase | 2.4000 kVA |
| 20 A | 240 V | Single-phase | 4.8000 kVA |
| 10 A | 208 V | Three-phase | 3.6027 kVA |
| 20 A | 208 V | Three-phase | 7.2053 kVA |
| 10 A | 480 V | Three-phase | 8.3138 kVA |
| 20 A | 480 V | Three-phase | 16.6277 kVA |
About the Amps to kVA Calculator
The amps to kVA calculator converts electrical current (amperes) and voltage (volts) into apparent power in kilovolt-amperes (kVA). kVA is used to rate transformers, generators, UPS systems, and electrical panels — it tells you the total electrical capacity required regardless of the load's power factor.
- Supports DC, single-phase AC, and three-phase AC power systems
- Calculates both VA (volt-amperes) and kVA (kilovolt-amperes)
- Uses the standard IEEE formulas: kVA = (A × V) ÷ 1,000 and kVA = (√3 × A × V) ÷ 1,000
- Includes a quick reference table for common voltages (120V, 240V, 208V, 480V)
- All calculations run in your browser — no data is sent to any server
How to Use the Amps to kVA Calculator
- 1
Select the power type
Choose DC for batteries and electronics, single-phase AC for standard household circuits, or three-phase AC for industrial and commercial systems.
- 2
Enter the current in amps
Type the ampere value from your circuit specification, equipment nameplate, or measured value. This is the line current (per phase for three-phase systems).
- 3
Enter the voltage in volts
Enter the line-to-neutral voltage for single-phase, or line-to-line voltage for three-phase systems (e.g., 208V or 480V).
- 4
Read the kVA result
The result updates instantly. The kVA value is the apparent power — use this to select a correctly rated transformer, UPS, or generator for your load.
Tip: When sizing a generator or UPS, always add a 20–25% safety margin above the calculated kVA to handle startup surges and future load growth.
Common Use Cases
Transformer Sizing
- • Determine the minimum kVA rating for a step-down transformer
- • Verify an existing transformer can handle a new load
- • Size distribution transformers for commercial buildings
Generator & UPS Selection
- • Calculate total kVA load to select the right generator size
- • Size a UPS for data center or critical equipment backup
- • Check that a portable generator covers your load during outages
Electrical Panel Planning
- • Determine apparent power demand for new electrical service
- • Verify panel capacity before adding circuits or equipment
- • Calculate load for permit applications and utility requests
HVAC & Industrial Equipment
- • Size three-phase power supply for large HVAC units and motors
- • Convert nameplate amps/volts to kVA for maintenance records
- • Determine apparent power for variable-frequency drive (VFD) systems
Solar & Battery Systems
- • Calculate inverter kVA requirements from battery bank current
- • Size a solar inverter to match panel output
- • Verify off-grid system capacity for specific loads
Education & Engineering
- • Verify hand calculations for electrical engineering coursework
- • Demonstrate apparent vs. real power in AC circuit analysis
- • Quick reference during electrical exams and certification prep
Frequently Asked Questions
What is kVA?
kVA (kilovolt-ampere) is the unit of apparent power in an electrical system. It represents the total power drawn from the supply, including both the useful real power (kW) and the reactive power (kVAR) caused by inductive or capacitive loads. One kVA equals 1,000 volt-amperes.
What is the formula to convert amps to kVA?
For single-phase (and DC): kVA = (A × V) ÷ 1,000. For three-phase: kVA = (√3 × A × V) ÷ 1,000, where √3 ≈ 1.7321 and V is the line-to-line voltage.
What is the difference between kVA and kW?
kW (kilowatt) is real power — the energy actually doing work. kVA is apparent power — what the electrical supply must provide. They are related by power factor: kW = kVA × PF. For purely resistive loads (space heaters, incandescent bulbs), PF = 1 so kW = kVA. For motors, computers, and fluorescent lighting, PF < 1 so kVA > kW.
Why is kVA used to rate transformers and generators instead of kW?
Transformers and generators are limited by the current and voltage they can handle — both of which contribute to heat and insulation stress regardless of power factor. Because their thermal limit is based on apparent power, kVA is the correct rating unit. The power factor of the load does not change the transformer's physical capacity.
What voltage should I use for a three-phase calculation?
Use the line-to-line voltage (also called phase-to-phase voltage). In North America the common three-phase voltages are 208V (low-voltage commercial), 480V (industrial), and 277/480V (large commercial). The formula kVA = (√3 × A × V) ÷ 1,000 already accounts for the three-phase factor.
How do I convert kVA to amps?
Rearrange the formula: for single-phase, A = (kVA × 1,000) ÷ V. For three-phase, A = (kVA × 1,000) ÷ (√3 × V). This is useful when you know the kVA rating of a transformer and need to find the maximum current it can supply.
Is my data safe? Does this tool send data to a server?
No data leaves your browser. All calculations happen entirely client-side using JavaScript. The values you enter are never uploaded or stored anywhere.