Amps to kW Calculator
Enter your electrical values below to convert current (amps) into real power (kilowatts).
What this amps to kW calculator does
This calculator converts electrical current in amps (A) to real power in kilowatts (kW). It supports three common scenarios: DC circuits, single-phase AC, and three-phase AC systems. Instead of doing manual calculations every time, you can quickly enter your values and get a clean result.
If you work with motors, generators, panels, or load planning, this conversion helps you estimate how much usable power a circuit is delivering.
amps to kW formulas you should know
DC circuits
kW = (V × I) / 1000
In DC systems, power factor is not used in the same way as AC, so the conversion is straightforward.
Single-phase AC
kW = (V × I × PF) / 1000
Power factor (PF) accounts for the difference between apparent and real power. For many practical loads, PF is less than 1, which means real power is lower than V × I.
Three-phase AC
kW = (√3 × V × I × PF) / 1000
In balanced three-phase systems, the √3 term (about 1.732) is required when using line-to-line voltage.
How to use the calculator
- Select your system type: DC, single-phase AC, or three-phase AC.
- Enter current in amps.
- Enter voltage in volts.
- For AC, enter power factor (typically between 0.8 and 1.0).
- Click Calculate kW to see real power.
Worked examples
Example 1: DC load
A DC system draws 40 A at 120 V. kW = (120 × 40) / 1000 = 4.8 kW
Example 2: Single-phase AC load
A single-phase device draws 20 A at 230 V with PF = 0.9. kW = (230 × 20 × 0.9) / 1000 = 4.14 kW
Example 3: Three-phase motor
A three-phase motor draws 30 A at 400 V with PF = 0.88. kW = (1.732 × 400 × 30 × 0.88) / 1000 ≈ 18.29 kW
Quick reference values
Single-phase AC at 230 V, PF = 0.9
| Current (A) | Power (kW) |
|---|---|
| 5 | 1.04 |
| 10 | 2.07 |
| 20 | 4.14 |
| 30 | 6.21 |
| 40 | 8.28 |
Three-phase AC at 400 V, PF = 0.9
| Current (A) | Power (kW) |
|---|---|
| 10 | 6.24 |
| 20 | 12.47 |
| 30 | 18.71 |
| 50 | 31.18 |
| 100 | 62.35 |
Common mistakes to avoid
- Using AC formulas for DC circuits.
- Forgetting power factor in AC calculations.
- Using phase voltage instead of line voltage in three-phase calculations.
- Mixing units (for example, entering kV as V without conversion).
- Assuming PF = 1 for all real-world equipment.
FAQ
Can I convert amps to kW without voltage?
No. You need voltage to convert current into power. Amps alone are not enough.
What if I do not know the power factor?
Use the equipment nameplate or manufacturer data. If unavailable, 0.8 to 0.95 is a common estimate for many AC loads.
Is this output input power or mechanical output power?
This calculator gives electrical real input power (kW). Motor shaft output is lower and depends on efficiency.
Final note
This amps to kW conversion calculator is a fast way to estimate power demand for design checks, electrical sizing, and energy planning. For critical engineering decisions, always verify values with full system data and applicable electrical standards.