A to kVA Calculator: Convert Amps to Kilovolt-Amps

An A to kVA calculator converts electrical current in amperes (A) into apparent power in kilovolt-amperes (kVA). Enter the current and voltage, then select single-phase or three-phase power to calculate the result; for AC calculations, you also need the power factor.

Formula

For single-phase AC, apparent power is S (kVA) = V × I ÷ (1,000 × PF). For three-phase AC using line-to-line voltage and line current, it is S (kVA) = √3 × V × I ÷ (1,000 × PF). The calculator combines the two with a phase multiplier: S = V × I × M ÷ (1,000 × PF).

• S is apparent power in kilovolt-amperes (kVA).
• V is voltage in volts (V).
• I is current in amperes (A).
• M is 1 for single-phase power or √3 (about 1.732) for three-phase power.
• PF is power factor, a unitless number from 0 to 1. The calculator requires a value greater than zero because division by zero is undefined.

The displayed kVA result is rounded to two decimal places. The VA output is the same apparent-power quantity expressed in volt-amperes, rounded to a whole VA. The formula assumes the voltage and current are the appropriate RMS values for the selected phase arrangement and that the stated power factor applies.

Worked Example

Using the defaults—10 A, 230 V, power factor 0.8, and single-phase power—the phase multiplier is 1.

1. Multiply current by voltage: 10 A × 230 V = 2,300 VA before adjusting for power factor.
2. Divide by the power factor: 2,300 ÷ 0.8 = 2,875 VA.
3. Convert volt-amperes to kilovolt-amperes: 2,875 ÷ 1,000 = 2.875 kVA.

Rounded to two decimal places, the calculator’s headline result is 2.88 kVA. Its secondary output is 2,875 VA.

When to Use an Amps-to-kVA Conversion

Use this calculation when you know a current, a voltage, and the relevant power factor, and want to express the apparent power associated with them. It can help make electrical specifications easier to compare, since current and voltage describe circuit conditions while kVA describes apparent power. It is a conversion based on supplied values, not a measurement of the actual load.

Choose the phase option to match the system. In a typical three-phase calculation, enter the line-to-line voltage and the current in one line. Do not enter a phase-to-neutral voltage with the three-phase formula unless the specific calculation calls for it. In single-phase power, use the voltage across the load and its current.

For direct current (DC), power in watts is voltage multiplied by current. There is no AC power factor or three-phase multiplier in that basic DC relationship. This calculator is intended for AC apparent power, so its phase and power-factor assumptions should not be applied blindly to DC circuits.

What kVA Means—and How It Differs from kW

Volt-amperes describe apparent power: the product of RMS voltage and RMS current, adjusted for phase in a three-phase system. Kilovolt-amperes are 1,000 volt-amperes. Kilowatts (kW), by contrast, describe real power—the rate at which electrical energy is transferred to useful work or heat. In an AC system, the relationship is kW = kVA × PF, when the same power-factor definition and operating conditions apply.

For example, 10 kVA at a power factor of 0.8 corresponds to 8 kW of real power: 10 × 0.8 = 8. This does not mean that every device with a 10 kVA rating continuously consumes 10 kW. Nor can kW be found from amps and volts alone in an AC calculation if power factor is unknown.

Power factor reflects how real power relates to apparent power. For a simple sinusoidal load, it is commonly described using the phase relationship between voltage and current. With nonlinear loads, waveform distortion can also affect the relationship. Use a reliable value for the actual equipment or measurement; assuming 1 may overstate the real power associated with a given kVA.

Inputs, Units, and Common Errors

• Check the voltage units. Enter volts, not kilovolts. For example, 0.4 kV is 400 V; entering 0.4 as though it were volts changes the answer by a factor of 1,000.
• Match the phase convention. The three-phase expression uses line-to-line voltage with line current. Confusing line and phase values can produce an incorrect result.
• Use a credible power factor. A value must be greater than zero and no more than 1. If it is not known, the calculator cannot determine a dependable kVA value from AC current and voltage alone.
• Keep RMS quantities consistent. Electrical ratings and common AC calculations generally use RMS voltage and current. Mixing peak values with RMS values leads to errors.
• Understand rounding. The calculation uses the entered values and rounds only the displayed result. A result of 2.88 kVA does not mean the unrounded value was exactly 2.88 kVA.

Amps and volts may be used in countries that also list equipment in horsepower, watts, or other units. Convert inputs to volts and amperes before using this calculator. It does not convert US customary measurements such as horsepower directly; that requires additional information and a separate conversion.

Limits and Practical Interpretation

The calculation cannot confirm that a generator, transformer, or other equipment is appropriate for a particular installation. Actual selection depends on operating conditions, starting or inrush current, load variation, system configuration, and the equipment’s documented ratings. A calculated kVA value is an arithmetic result, not a safety approval or sizing recommendation. For equipment selection or electrical work, consult the relevant specifications and a qualified professional.

For a changing load, one current and power-factor entry represents only the conditions those values describe. A brief peak, an average, and a continuous operating value are not interchangeable. Likewise, a power factor measured at one load may differ at another. Use measurements or manufacturer data that match the question you are trying to answer.

Frequently Asked Questions

How do I convert amps to kVA?
For single-phase AC, multiply volts by amps and divide by 1,000 times the power factor. For three-phase AC using line-to-line voltage and line current, multiply that numerator by √3 as well.

Can I calculate kVA from amps alone?
No. You also need voltage. For AC, you need the power factor too, and a three-phase calculation must use the correct phase formula and voltage convention.

What power factor should I enter?
Use a documented or measured value for the load and operating condition. A power factor of 1 is appropriate only when that value is known or explicitly assumed; it should not be treated as a default fact about all equipment.

Is kVA the same as kW?
No. kVA is apparent power; kW is real power. For the same AC conditions, kW equals kVA multiplied by power factor.

Which voltage do I use for three-phase kVA?
Use line-to-line voltage with line current in the standard √3 formula. If your available value is phase-to-neutral voltage, check the system arrangement and use a formula that matches those values.

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in amps | Current | A | 10 | 0
in volts | Voltage | V | 230 | 0
in pf | Power factor | - | 0.8 | 0 | 1
sel phase | Phase | Single-phase=1, Three-phase=1.7320508075688772
out kva | Apparent power | kVA | amps * volts * phase / (1000 * pf) | 2
out va | Apparent power | VA | amps * volts * phase / pf | 0