Amps to kW Calculator: Convert Electrical Current

An amps to kW calculator estimates electrical power in kilowatts from current in amperes, using the voltage and the type of electrical supply. Enter amps, volts, and—when relevant—the power factor; the result is real power in kW, with the assumptions made explicit.

Formula

The calculator uses the standard relationship between current and power. For single-phase AC, real power is kW = V × A × PF ÷ 1,000. For balanced three-phase AC, it is kW = √3 × V × A × PF ÷ 1,000.

• kW is real power, in kilowatts.
• V is voltage in volts.
• A is current in amperes (amps).
• PF is power factor, a unitless value from 0 to 1 in this calculator.
• √3, approximately 1.732, applies to balanced three-phase power when voltage is line-to-line and current is line current.

The displayed kVA is apparent power: kVA = phase factor × V × A ÷ 1,000, where the phase factor is 1 for single-phase and √3 for three-phase. Real power equals apparent power multiplied by power factor. The calculator assumes AC and, for the three-phase option, a balanced load.

Worked Example

Using the defaults—10 A, 230 V, single-phase, and a power factor of 1—the real power calculation is:

1. Multiply voltage by current: 230 V × 10 A = 2,300 VA.
2. Apply the power factor: 2,300 × 1 = 2,300 W.
3. Convert watts to kilowatts: 2,300 ÷ 1,000 = 2.30 kW.

Apparent power is 230 × 10 ÷ 1,000 = 2.30 kVA. With a power factor of 1, real power and apparent power have the same numerical value.

How to Choose the Right Inputs

Use the voltage that belongs with the current measurement and choose the matching supply type. A common source of error is using a voltage measured between two phase conductors with a formula that expects phase-to-neutral voltage, or selecting three-phase when the circuit is single-phase.

• Single-phase: Select this for a single-phase supply. The formula uses the supply voltage and current.
• Three-phase: Select this for a three-phase supply when the voltage entered is line-to-line voltage and the current is line current. The formula assumes a balanced load.
• Power factor: Enter a known value from suitable equipment documentation or a measurement. If it is unknown, a result with PF = 1 is an apparent-power-equivalent upper calculation, not necessarily the actual real power.

For example, 10 A at 230 V on single-phase with PF 0.8 gives 230 × 10 × 0.8 ÷ 1,000 = 1.84 kW. At the same voltage and current, apparent power remains 2.30 kVA. A three-phase calculation is not interchangeable with this example: the supply configuration and voltage convention must match.

When to Use It—and What It Does Not Tell You

Use the conversion when you have a current value and need an estimate of electrical power under stated supply conditions. It can help interpret equipment data or compare current and power figures, provided the voltage, phase arrangement, and power factor are known or appropriately assumed.

Amps measure current; kilowatts measure real power. There is no single universal amps-to-kW conversion because current alone does not specify voltage, and AC real power also depends on power factor. For DC, the basic relationship is W = V × A; if an ideal DC calculation is needed, use a power factor of 1 and the single-phase multiplier. This does not account for voltage variation, losses, or equipment behavior.

The calculator reports an electrical power estimate, not energy consumption. Energy depends on how long power is used: at a steady 2 kW for 3 hours, energy use is 6 kWh. It also does not establish whether a circuit, conductor, generator, or appliance is suitable for a particular load.

Common Mistakes and Limits

• Leaving out power factor: Assuming PF = 1 may overstate real AC power when PF is lower. It gives kVA as the numerical result, not necessarily kW.
• Mixing up phase types: The √3 factor is for balanced three-phase calculations with line-to-line voltage and line current. Applying it to single-phase, or using mismatched three-phase quantities, produces the wrong answer.
• Confusing kW and kVA: kW describes real power; kVA describes apparent power. They are equal only when PF is 1.
• Rounding too early: Keep the original readings and power factor through the calculation, then round the final result. The calculator displays kW and kVA to two decimal places.

Real installations can have unbalanced phases, changing loads, harmonics, or measurement uncertainty. A simple formula may not represent those conditions accurately. Use appropriate measurement information for precise power analysis, and do not use this conversion alone to select or size electrical equipment; consult a qualified professional for installation and safety decisions.

Frequently Asked Questions

How many kW is 1 amp?
It depends on voltage, supply type, and power factor. At 230 V single-phase and PF 1, 1 A is 0.23 kW. At other conditions, calculate using the matching formula.

How do I convert amps to kW on single-phase?
Multiply volts by amps and power factor, then divide by 1,000: kW = V × A × PF ÷ 1,000.

How do I convert amps to kW on three-phase?
For a balanced three-phase supply, multiply line-to-line volts by line amps and PF, then by √3; divide by 1,000. Make sure the voltage and current are the correct line quantities.

Can I convert amps to kW without knowing voltage?
No. Current alone is not enough to determine power. You also need voltage, and for AC real power you need power factor as well.

Is kW the same as kVA?
No. kVA is apparent power; kW is real power. For AC, kW equals kVA multiplied by power factor, so they match only at PF 1.

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in a | Current | A | 10 | 0
in v | Voltage | V | 230 | 0
sel ph | Supply type | Single-phase=1, Three-phase=1.7320508075688772
in pf | Power factor | - | 1 | 0 | 1
out kw | Real power | kW | ph * v * a * pf / 1000 | 2
out kva | Apparent power | kVA | ph * v * a / 1000 | 2