👤 By Why Calculator Team ✔ Reviewed by Matt Le (Founder of Why Calculator) 📅 Last Updated April 11, 2026
Amps to kW Calculator
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This Amps to kW Calculator helps you quickly convert electric current (amps) into power (kilowatts) for DC, single-phase AC, and three-phase AC circuits. Whether you're working with household appliances, industrial machines, or electrical installations, this tool makes power calculations easy.
Enter the current (A), voltage (V), and power factor (if applicable), and get the kW value instantly. It supports different voltage types and typical power factor values for accuracy. Use this calculator to estimate power requirements, optimize energy usage, or check electrical loads effortlessly.
How to Convert Amps to kW
To convert amps (A) to kilowatts (kW), you need to consider the type of circuit: DC, Single-phase AC, or Three-phase AC. The power calculation varies depending on the voltage type and power factor in AC circuits.
1. Formula for DC Circuits
For DC circuits, power is simply the product of voltage and current:
P(kW) = V × I / 1000
Example 1:
A 24V DC motor drawing 50A of current:
P(kW) = 24V × 50A / 1000
= 1200 / 1000 = 1.2kW
2. Formula for Single-Phase AC Circuits
For single-phase AC circuits, the power factor (PF) must be included in the formula:
P(kW) = V × I × PF / 1000
Example 2:
A 230V single-phase air conditioner with a current of 15A and a power factor of 0.85:
P(kW) = 230V × 15A × 0.85 / 1000
= 2936.25 / 1000
= 2.94kW
3. Formula for Three-Phase AC Circuits
For three-phase AC circuits, we use the square root of √3 (≈1.732) in the calculation:
P(kW) = √3 × V × I × PF / 1000
For line-to-line voltage:
P(kW) = 1.732 × V × I × PF / 1000
For line-to-neutral voltage:
P(kW) = 3 × V × I × PF / 1000
Example 3:
A 400V three-phase industrial motor with 20A current and a power factor of 0.9:
P(kW) = 1.732 × 400V × 20A × 0.9 / 1000
P(kW) = 12470.4 / 1000
= 12.47kW
| Current (A) | Voltage (V) | System Type | Power Factor (if applicable) | Power (kW) |
|---|---|---|---|---|
| 10 | 230 | DC | — | 2.30 |
| 20 | 400 | DC | — | 8.00 |
| 15 | 230 | AC Single-Phase | 0.9 | 3.10 |
| 30 | 415 | AC Single-Phase | 0.85 | 10.60 |
| 25 | 400 | AC Three-Phase | 0.9 | 15.59 |
| 50 | 415 | AC Three-Phase | 0.95 | 34.10 |
| 75 | 480 | AC Three-Phase | 0.9 | 56.06 |
| 100 | 600 | AC Three-Phase | 0.85 | 88.34 |
FAQs:
What is the power factor, and why is it important in AC circuits?
The power factor (PF) is the ratio of real power to apparent power in an AC circuit. A lower power factor reduces efficiency, so it must be included in AC power calculations. Typical values range from 0.8 to 0.95.
Can I convert amps to kW without knowing the voltage?
No, you must know the voltage (V) to convert amps (A) to kW. Power (kW) is calculated using voltage and current, and in AC circuits, the power factor is also required.
Why is the formula different for three-phase systems?
Three-phase systems use line-to-line or line-to-neutral voltages, and power is distributed across three phases. This requires multiplying by √3 (1.732) to account for phase balancing in the formula.
How many kW is 50A at 230V in a single-phase system?
Using the formula:
kW = 230V × 50A × 0.9 / 1000
= 10350 / 1000 = 10.35kW
This assumes a power factor of 0.9.
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