Amps to kVA Converter

Convert amperes (A) to kilovolt-amperes (kVA) for electrical systems. This converter handles both single-phase and three-phase circuits, giving you accurate apparent power ratings for generators, transformers, and distribution systems.

Line voltage for single phase

Quick Conversions

Recent Conversions

Amps to kVA Conversion Table

Common conversions for single-phase 230V systems (typical UK domestic supply):

Current (A) Voltage (V) Apparent Power (kVA)
102302.30
162303.68
202304.60
322307.36
402309.20
5023011.50
6323014.49
8023018.40
10023023.00
12523028.75

Three-phase 400V line-to-line conversions (common UK commercial/industrial supply):

Current (A) Voltage (V) Apparent Power (kVA)
1640011.09
2540017.32
3240022.17
4040027.71
5040034.64
6340043.64
8040055.43
10040069.28
12540086.60
160400110.85

Conversion Formulas

Single-Phase Systems

The apparent power in kilovolt-amperes is found by multiplying current by voltage, then dividing by 1000:

S(kVA) = I(A) × V(V) / 1000

Where:

  • S = Apparent power in kilovolt-amperes (kVA)
  • I = Current in amperes (A)
  • V = Voltage in volts (V)

Three-Phase Systems

Line-to-Line Voltage:

S(kVA) = √3 × I(A) × VL-L(V) / 1000

This is the most common method for three-phase systems in the UK, where the line-to-line voltage is typically 400V.

Line-to-Neutral Voltage:

S(kVA) = 3 × I(A) × VL-N(V) / 1000

Used when you know the phase voltage (line-to-neutral), which is typically 230V in UK three-phase systems.

Step-by-Step Conversion

  1. Identify whether your system is single-phase or three-phase
  2. Measure or obtain the current value in amperes
  3. Determine the voltage – for three-phase, clarify if it’s line-to-line or line-to-neutral
  4. Apply the appropriate formula based on your system type
  5. Divide the result by 1000 to convert from VA to kVA

Practical Examples

Domestic Single-Phase

A typical UK home has a 230V single-phase supply with a 100A main breaker. What’s the maximum apparent power?

S = 100A × 230V / 1000 = 23 kVA

This represents the total capacity available to the property, though actual demand is typically much lower.

Commercial Three-Phase

A workshop has a 400V three-phase supply with a 63A rated circuit. What’s the apparent power capacity?

S = 1.732 × 63A × 400V / 1000 = 43.64 kVA

This three-phase supply provides significantly more power than a single-phase equivalent, making it suitable for heavy machinery.

What’s the Difference?

Term Symbol What It Means
Amperes A The amount of electrical current flowing through a circuit
Kilovolt-Amperes kVA Apparent power – the total power in an AC circuit (voltage × current)
Kilowatts kW Real power – the actual power doing useful work (kVA × power factor)
Power Factor PF Ratio of real power to apparent power (typically 0.8 to 1.0)

Important: kVA represents apparent power, which is the total power supplied. In real systems, not all this power does useful work due to the power factor. To find actual power (kW), you’d multiply kVA by the power factor. For purely resistive loads like heaters, the power factor is 1.0, so kVA equals kW.

UK Electrical Standards

Understanding these standards helps you apply the right voltages:

  • Domestic single-phase: 230V ±10% (previously 240V before harmonisation)
  • Three-phase line-to-line: 400V ±10% (previously 415V)
  • Three-phase line-to-neutral: 230V ±10%
  • Frequency: 50 Hz across the UK network

The relationship between three-phase voltages: VL-L = √3 × VL-N, which is why 400V ÷ √3 ≈ 230V.

FAQs

What’s the difference between kVA and kW?
kVA measures apparent power (total power in the circuit), while kW measures real power (power actually doing work). They’re related by the power factor: kW = kVA × PF. For resistive loads, they’re equal. For motors and other inductive loads, kW is typically 80-90% of kVA.
Why do I need to know the phase type?
Single-phase and three-phase systems use different formulas. Three-phase distributes power across three conductors, requiring a √3 multiplier in the equation. Getting this wrong means your kVA result will be off by about 73%.
Can I use this for DC circuits?
No, kVA is an AC concept. For DC circuits, you’d simply calculate power in kilowatts (kW) since DC has no reactive component. The formula would be: kW = I × V / 1000.
What voltage should I use for UK three-phase?
Use 400V for line-to-line voltage, which is standard across UK industrial and commercial installations. If you’re measuring phase voltage (line-to-neutral), use 230V and select the appropriate option in the converter.
How do I find the current rating of my equipment?
Check the nameplate on the equipment or the circuit breaker protecting it. The nameplate typically shows voltage, current, and power ratings. For installed circuits, look at the MCB (miniature circuit breaker) rating in your distribution board.
Why does my generator show kVA instead of kW?
Generators are rated in kVA because they must supply the total apparent power, regardless of the load’s power factor. This ensures the generator can handle all types of loads. The actual kW output depends on what you connect to it.

Power Converter

Related electrical power conversions you might need:

kVA to Amps

Reverse conversion from apparent power to current

kW to Amps

Real power to current (requires power factor)

kVA to kW

Apparent power to real power conversion

HP to kVA

Horsepower to apparent power for motors

Watts to Amps

Power to current conversion

Volts to Amps

Voltage to current (requires power/resistance)

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