Single-Phase Amps to kW Calculator
Quick explanation
Use current in amps and voltage to estimate real power in kilowatts (kW). For the reverse, use kW to amps. For apparent power, try amps to kVA. For formula background, see the how to convert kW to amps guide.
Estimated real power: 4.8 kW
How to convert single-phase amps to kW
To estimate real power in kilowatts from current in amps, include voltage and the correct phase model. Amps and kW are different electrical quantities; a voltage value is required to convert between them.
This calculator uses the single-phase relationship only, and assumes unity power factor. For loads with reactive components such as motors, the actual real power will be lower than this estimate. For three-phase conversions, use a dedicated three-phase calculator.
How to convert
Single-phase formula
Real power in kilowatts equals amps multiplied by volts, divided by 1000.
kW = (A × V) / 1000
kilowatts = (amps × volts) / 1000
Worked examples
Question: What is real power for 25 A at 240 V single phase?
Solution: kW = (25 × 240) / 1000 = 6.0 kW
Question: What is real power for 15 A at 120 V single phase?
Solution: kW = (15 × 120) / 1000 = 1.8 kW
Question: What is real power for 30 A at 240 V single phase?
Solution: kW = (30 × 240) / 1000 = 7.2 kW
Common mistakes and notes
- This formula assumes unity power factor. For loads with reactive components, actual real power (kW) will be lower than this estimate.
- This page is single-phase only.
- kW is real power; kVA is apparent power. They differ when power factor is less than 1.
- Final sizing should be validated with local code and manufacturer specs.
Assumptions
- REVIEW: Uses simplified single-phase estimate kW = (A x V) / 1000.
- Assumes unity power factor; actual real power will be lower for loads with power factor less than 1.
- Results are informational estimates and require engineering validation.
Worked example
Example: 30 A at 240 V = 7.2 kW.
FAQ
How do you convert amps to kW?
Use kW = (A x V) / 1000 for a single-phase estimate. Voltage is required because amps and kilowatts measure different electrical quantities.
What is 20 A at 240 V in kW?
kW = (20 x 240) / 1000 = 4.8 kW.
What is 15 A at 120 V in kW?
kW = (15 x 120) / 1000 = 1.8 kW.
Is kW the same as kVA?
Not always. kW is real power, the work actually done. kVA is apparent power and is always equal to or greater than kW. For pure resistive loads, they are equal. For motors and electronics with reactive components, kVA is higher.
Can I use this for three-phase circuits?
No. This calculator uses the single-phase formula only. Three-phase conversions require a different formula.
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⚠️ Sanity Check Only
This tool provides informational estimates only. It is not professional engineering advice. Electrical work is dangerous and governed by strict local codes.
Before you start:
- Verify these results with a licensed electrician.
- Cross-reference with the latest Electrical Code (NEC/CEC).
- Never work on live circuits.