kVA to Amps Calculator: Convert Apparent Power to Current (1φ & 3φ)

Convert kVA to amps using the voltage and phase connection being checked. For single-phase, use I = kVA × 1000 ÷ V; for balanced three-phase, use I = kVA × 1000 ÷ (√3 × V) with line-to-line voltage. Total kVA needs no extra power-factor adjustment. The result is current at the stated rating or operating load, not a breaker or cable selection.

Compare common voltages in the tables, follow six worked examples, and distinguish transformer primary current, secondary current and UPS output current. The 400 V and 415 V columns let you compare those systems without assuming they are identical to 380 V.

kVA to Amps Conversion Table — Single-Phase & Three-Phase

Values use the stated total kVA and voltage, rounded to two decimals. They do not assume PF or select an equipment rating.

Table 1 — Single-Phase kVA to Amps

Table 2 — Three-Phase kVA to Amps (Line-to-Line Voltage)

Example: 100 kVA gives 144.34 A at 400 V, 139.12 A at 415 V, or 120.28 A at 480 V.

75 kVA transformer: primary and secondary amps

A three-phase 75 kVA transformer rated 480 V primary and 208 V secondary corresponds to 90.21 A primary and 208.18 A secondary. Enter the same 75 kVA twice and change voltage from 480 to 208. These are rated-current relationships; actual input includes losses and excitation, and actual load can be below rating.

Step-by-Step Formulas: How to Convert kVA to Amps

The conversion from kVA to amps depends on whether you have a single-phase or three-phase system. Both formulas come from the same principle: apparent power (S) equals voltage times current. The only twist is the √3 factor in three-phase circuits, which accounts for the 120° phase offset between the three line conductors.

Formula 1 — Single-Phase kVA to Amps

Use the voltage across the single-phase load or winding. It can be line-to-neutral or line-to-line: a 240 V load supplied between two lines still uses the single-phase formula without √3. The factor 1000 converts kVA to VA.

Example: A 10 kVA single-phase generator at 240 V.
I = (10 × 1000) ÷ 240 = 10000 ÷ 240 = 41.67 A.

Formula 2 — Three-Phase kVA to Amps

Here V_LL is line-to-line voltage and √3 ≈ 1.7320508. The formula assumes a balanced three-phase load. For an unbalanced system, establish each branch connection and load separately; delta or line-to-line branches cannot all be treated as line-to-neutral loads.

Example: A 75 kVA three-phase transformer at 480 V.
I = (75 × 1000) ÷ (1.7321 × 480) = 75000 ÷ 831.38 = 90.21 A.

Formula 3 — When the starting value is kW instead of kVA

Use these formulas only when your starting value is electrical input power in kW. For example, 22 kW of electrical input at PF 0.85 corresponds to 22 ÷ 0.85 = 25.88 kVA. If 22 kW is instead motor shaft output, divide by efficiency first to obtain electrical input, then divide by PF. Once you have kVA, use Formula 1 or 2 without another PF adjustment.

Why the formulas work

Apparent power is V × I for single-phase and √3 × V_LL × I for a balanced three-phase load. Rearranging gives current. See Schneider Electric’s transformer kVA and amperage calculation guide for the rating relationships.

kVA vs kW vs kVAR — What Is the Difference?

These three quantities describe different aspects of AC power. Confusing them leads to undersized equipment, tripped breakers, and utility penalties. Here is a clear comparison.

For sinusoidal conditions, the power triangle gives kVA² = kW² + kVAR². Distorted waveforms require additional care when interpreting this triangle. A kVA rating expresses apparent power; the corresponding real power is kVA × PF. Converting kVA to amps needs no additional PF term. A calculated operating current does not by itself determine motor conductor or protection ratings: use the applicable design rules and distinguish code-table current from motor nameplate current.

Inverse Conversion: Amps to kVA

To go from amps back to kVA, multiply instead of dividing.

You can also use our calculator above — switch to “Amps → kVA” mode. For a deeper look at the amp-to-kVA direction, see our Amperes to VA calculator.

6 Solved Examples — Real-World kVA to Amps Conversions

kVA to Amps in Electric Motors & Transformers

Transformer Nameplates

Check total kVA, voltage and phase connection on each side. A 75 kVA three-phase rating gives 90.21 A at 480 V and 10.41 A at 4160 V. Primary protection, secondary protection and conductor protection are distinct checks.

Motor kVA vs Motor kW

For motor shaft-output kW, use input kVA = shaft kW ÷ (efficiency × PF). For 22 kW shaft output, efficiency 0.91 and PF 0.86, input kVA = 28.11. At 480 V three-phase, current = 33.81 A. Do not divide measured electrical input kW by efficiency again.

Compare input types with the three-phase current calculator. Calculated running current is distinct from any required motor code-table current.

Generator Sizing

Rated kVA and voltage determine rated output current. Selection also needs the generator’s kW limit, load sequence, motor starting and transient requirements. A running-current conversion cannot establish starting capability.

Quick Equivalences — kVA to Amps by Voltage

These values use balanced three-phase loads unless marked single-phase. Voltage and connection must accompany every answer.

Frequently Asked Questions

How do I convert kVA to Amps?

Divide kVA × 1000 by your voltage. For three-phase, also divide by √3 (1.7321). Formula: I = (kVA × 1000) ÷ V for single-phase, I = (kVA × 1000) ÷ (√3 × V) for three-phase. Example: 50 kVA at 480 V 3φ = 60.14 A.

Can I convert kVA to Amps without knowing voltage?

No. Voltage is essential because amps = power ÷ voltage. Without voltage, you cannot determine current. If the voltage is unknown, check the equipment nameplate, the utility service entrance, or the transformer secondary rating.

What is the difference between kVA and kW?

kVA is apparent power (voltage × current, no PF). kW is real (active) power, which accounts for power factor: kW = kVA × PF. Transformers and generators are rated in kVA; motors and heaters are rated in kW. When converting kVA to amps, PF is not needed.

How many amps is 1 kVA at 120 V?

8.33 A. Calculation: (1 × 1000) ÷ 120 = 8.33 A. This is a single-phase result. At 240 V single-phase, 1 kVA = 4.17 A.

How many amps is 125 kVA at 480 V three-phase?

125000 ÷ (√3 × 480) = 150.35 A. This is the line current at 125 kVA on a balanced 480 V three-phase system.

How many amps is 200 kVA at 380 V three-phase?

200000 ÷ (√3 × 380) = 303.87 A. At 400 V, the same 200 kVA gives 288.68 A.

Why does my calculated current differ from the nameplate?

Check whether the rating is input or output, kW or kVA, total three-phase or one winding, and which voltage tap applies. Actual current also depends on loading, losses and operating conditions.

Do I need power factor to convert kVA to amps?

No. Use apparent power and voltage for the same side of the circuit. PF is needed to convert electrical kW to kVA; it is not applied again after kVA is known. Use the appropriate single-phase or balanced three-phase formula.

How do I convert amps to kVA?

Multiply: kVA = (I × V) ÷ 1000 for single-phase, or kVA = (I × V × √3) ÷ 1000 for three-phase. Example: 100 A at 480 V 3φ = (100 × 480 × 1.7321) ÷ 1000 = 83.14 kVA.

What voltage should I use — line-to-line or line-to-neutral?

For three-phase, always use line-to-line voltage (e.g., 208, 380, 480 V) with the √3 formula. For single-phase loads fed from line to neutral, use the L-N voltage (e.g., 120 V). For single-phase loads fed line to line (e.g., 240 V dryer circuit), use the L-L voltage without √3.

How do I size a transformer from amps?

First calculate load kVA from current, voltage and phase connection. Then check available equipment ratings, simultaneous loading, starting conditions, harmonics and the manufacturer’s requirements. A fixed growth percentage is not a complete selection method.

Is the kVA-to-amps conversion the same for AC and DC?

No. kVA is an AC concept (it accounts for phase angle). In DC circuits, power is simply P = V × I (watts). There is no reactive component and no √3 factor. Do not apply AC kVA formulas to DC systems.

References: Schneider Electric — transformer kVA and amperage calculations; Eaton 93E installation manual, for separate rectifier input, bypass and output requirements.

Related Conversions

• Three-phase current calculator: calculate amps from kW, HP or kVA.
• mm² to AWG converter: compare metric wire cross sections with AWG sizes.
• Amperes to VA Calculator — inverse of this page (amps → VA/kVA)
• Amps to kW Calculator — when you need real power from current
• Amps to Watts Calculator — single-phase and three-phase watt conversions
• Amps to HP Calculator — from current directly to horsepower
• Transformer kVA Sizing Calculator — size your transformer from demand load
• Balanced and Unbalanced Load Calculation — handle phase imbalance properly
• UPS Sizing Calculator (kVA/kW) — exact UPS size for IT loads