Single-Phase kW to Amps Calculator
Quick explanation
Use real power in kilowatts (kW) and voltage to estimate current in amps. For the reverse, use amps to kW. Need apparent power instead? Try kVA to amps. For the formula walkthrough, read the how to convert kW to amps guide.
Estimated current: 20.833 A
How to convert single-phase kW to amps
To convert real power in kilowatts (kW) to current in amps (A), you need voltage and a phase assumption. kW and amps measure different electrical quantities; you cannot convert between them without knowing the voltage.
This calculator applies the single-phase formula only. If you need three-phase conversion, use a dedicated three-phase calculator. For apparent power (kVA) instead of real power, use the kVA to amps calculator.
How to convert
Single-phase formula
Current in amps equals 1000 times real power in kilowatts divided by RMS voltage in volts.
A = (kW × 1000) / V
amps = (kilowatts × 1000) / volts
Worked examples
Question: What is current for 3 kW at 120 V single phase?
Solution: A = (3 × 1000) / 120 = 25 A
Question: What is current for 7.5 kW at 240 V single phase?
Solution: A = (7.5 × 1000) / 240 = 31.25 A
Question: What is current for 1.2 kW at 240 V single phase?
Solution: A = (1.2 × 1000) / 240 = 5 A
Common mistakes and notes
- This formula assumes unity power factor. Real motors and electronics may draw more current than this estimate.
- This page is single-phase only.
- Do not confuse kW (real power) with kVA (apparent power); they are only equal for resistive loads.
- These are planning estimates and can differ from measured current.
Assumptions
- REVIEW: Uses simplified single-phase estimate A = (kW x 1000) / V.
- Assumes unity power factor; actual current will be higher for loads with power factor less than 1.
- Results are informational estimates and require engineering validation.
Worked example
Example: 7.5 kW at 240 V = 31.25 A.
FAQ
How do you convert kW to amps?
Use A = (kW x 1000) / V for a single-phase estimate. You need voltage because kilowatts and amps measure different electrical quantities.
How many amps is 5 kW at 240 V?
A = (5 x 1000) / 240 = 20.833 A.
How many amps is 1 kW at 120 V?
A = (1 x 1000) / 120 = 8.333 A.
What is the difference between kW and kVA?
kW is real power, the work actually done. kVA is apparent power and includes reactive loads. For resistive loads like heaters, kW and kVA are equal. For motors and some electronics, kW is lower than kVA.
Can I use this for three-phase circuits?
No. This calculator uses the single-phase formula only. Three-phase conversions require a different formula that includes the square root of 3.
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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.