Volt-Amperes to Amps Converter (VA to A & Current Calculator

Volt-Amperes (VA) to Amperes (A), Ohm's Law & Circuit Protection

Volt-Amperes (S) measure total apparent power, from which line current (I in Amperes) is calculated based on circuit voltage and phase configuration:

• **

• Universal VA to Amps Formulas**:

• Single-Phase Circuits (1Φ):

I_Amps = S_VAV_Volts

Example: 1,800 VA @ 120V I = (1,800) / (120) = 15.00 Amperes

• Three-Phase Circuits (3Φ Balanced Line-to-Line):

I_Amps = S_VA√(3) × V_Line-to-Line = S_VA1.73205 × V_L-L

Example: 30,000 VA @ 208V 3Φ I = (30,000) / (1.73205 × 208) = (30,000) / (360.27) = 83.27 Amperes

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• The NEC 125% Continuous Load Overcurrent Rule (NEC 210.20)**:

• Loads operating continuously for 3 or more hours must not exceed 80% of the breaker rating (or breaker must be at least 125\% of load current):

I_Breaker Rating I_Full-Load × 1.25

• **

• Standard North American Voltage and Breaker Sizing Standards**:

• 120V 1Φ: 1,440 VA continuous 15A Breaker / 14 AWG

• 120V 1Φ: 1,920 VA continuous 20A Breaker / 12 AWG

• 240V 1Φ: 5,760 VA continuous 30A Breaker / 10 AWG

• 240V 1Φ: 9,600 VA continuous 50A Breaker / 6 AWG

How to Use This Calculator

Enter your Apparent Power (Volt-Amperes / VA) (e.g. 1800 in VA), Operating Voltage (Volts / V_RMS) (e.g. 120, 208, 240, 480 in V), Circuit Electrical Phase — choose from Single-Phase (1Φ: I = VA / V), Three-Phase Line-to-Line (3Φ: I = VA / (√3 × V)), and Electrical Equipment Benchmark — choose from Custom VA & Voltage, 1,500 VA Rackmount Server UPS (120V 1Φ) → 12.50 A, 1,800 VA Max 15A Branch Circuit (120V 1Φ) → 15.00 A. Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Formula Reference: Volt-Amperes to Amps Converter (VA to A & Current Calculator)

Input variables:

apparentPowerVaInput — Apparent Power (Volt-Amperes / VA)

operatingVoltageVoltsInput — Operating Voltage (Volts / V_RMS)

electricalPhaseSelect — Circuit Electrical Phase

Computed outputs:

fullLoadCurrentAmps — Full-Load Line Current (Amperes / A)

necRecommendedBreakerAmps — Recommended Circuit Breaker (NEC 125% Rule)

apparentPowerKilovoltAmps — Apparent Power in kVA

realPowerAtEightyPercentPfWatts — Real Power (Watts @ 0.80 PF)

Mathematical relationships extracted from calculation logic:

amps = safeDiv(va, Math.sqrt(3.0) * volts)

minBreaker = amps * 1.25

recBreaker = standardBreakers[standardBreakers.length - 1]

kva = va / 1000.0

watts80 = va * 0.80

Standard: NIST Handbook 44 and BIPM SI unit definitions

Worked Example

An electrician wiring an electric clothes dryer rated at 5,760 VA on a 240V single-phase circuit calculates the line current as I = 5,760 / 240 = 24.0 Amps, specifying a 30A 2-pole circuit breaker with 10 AWG copper wire.

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.