Quick start
- Enter the kilowatt rating from the motor, inverter, heater, equipment label, or project note.
- Enter the supply voltage and choose DC, single-phase AC, or three-phase AC.
- Enter power factor for AC loads and efficiency when the kW rating is output power instead of input power.
Best uses
Start here if one of these sounds like your job. The examples below show which inputs matter most.
- Estimate current for a kW-rated load.
- Turn a motor kW rating into a rough running-current estimate.
- Compare DC, single-phase AC, and three-phase AC current.
- See how power factor changes AC amperage.
What this calculator is solving
The Kilowatts to Amps Calculator turns a power rating, voltage, phase type, power factor, and efficiency into an estimated running current in amps.
Match each input label on the calculator to the kilowatt rating, supply voltage, DC or AC phase type, power factor, and efficiency from the equipment label or specification when it is available.
The formula in plain language
In plain language: Input watts = kW x 1,000 / (efficiency / 100). DC amps = input watts / volts. Single-phase AC amps = input watts / (volts x power factor). Three-phase AC amps = input watts / (volts x sqrt(3) x power factor). The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
First convert output power to input watts: input watts = kW x 1,000 / (efficiency / 100). For DC, amps = input watts / volts. For single-phase AC, amps = input watts / (volts x power factor). For three-phase AC, amps = input watts / (volts x sqrt(3) x power factor).
How to read the answer
Read amps as an estimated running current. The input-watts line explains how efficiency changed the power value before the current formula was applied.
- The main answer is estimated running current in amps.
- Input watts after efficiency shows the power value the calculator used before solving current.
- Power factor, phase type, and efficiency explain why equal kW values can produce different amp estimates.
- Use the result for comparison or planning before checking the equipment nameplate, manufacturer instructions, code rules, and a qualified reviewer.
Common mistakes to avoid
Most kW-to-amps mistakes come from treating kW like kVA, guessing power factor or efficiency, or using a running-current estimate as if it were a final breaker or conductor size.
- Do not confuse kW with kVA.
- Do not assume power factor is 1 for every AC load.
- Do not leave efficiency at 100% when the rating is output power and losses matter.
- Do not use running current alone for breaker sizing, conductor sizing, voltage drop, motor starting current, duty cycle, or code compliance.
Quick 5 kW motor example
Say a motor is rated 5 kW output, runs from 240 V single-phase power, has 0.9 power factor, and is 90% efficient. First divide 5,000 W by 0.9 to get 5,555.56 input W.
Then divide 5,555.56 by 240 x 0.9. The running-current estimate is about 25.72 A before you account for nameplate requirements, starting current, conductor rules, breaker rules, and the installation environment.
Three-phase and DC checks
For a 15 kW three-phase load at 480 V, 0.88 power factor, and 92% efficiency, input power is about 16,304.35 W. Divide by 480 x sqrt(3) x 0.88 to get about 22.27 A.
For a 1.2 kW DC load at 48 V and 100% efficiency, divide 1,200 W by 48 V to get 25 A. That quick DC check is useful for battery, inverter, and low-voltage equipment planning.
- Use DC math only for DC loads.
- Use the three-phase formula with sqrt(3) for balanced three-phase line-to-line voltage.
- Use a kVA calculator when the label gives apparent power instead of real power in kW.
- Use manufacturer data and a qualified professional for circuit sizing and electrical safety decisions.
Research and references
These references help check the measurements, units, limits, or safety notes used in this guide.
Worked examples for Kilowatts to Amps Calculator
5,555.56 input W and about 25.72 A
16,304.35 input W and about 22.27 A
25 A
About 16.67 A
About 34.38 A
About 23.15 A vs 25.72 A
FAQ in plain language
When should I use the Kilowatts to Amps Calculator?
Use it when your task matches one of these common needs: Estimate current for a kW-rated load. Turn a motor kW rating into a rough running-current estimate. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Kilowatts to Amps Calculator doing with my inputs?
In plain language: Input watts = kW x 1,000 / (efficiency / 100). DC amps = input watts / volts. Single-phase AC amps = input watts / (volts x power factor). Three-phase AC amps = input watts / (volts x sqrt(3) x power factor). The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Kilowatts to Amps Calculator inputs mean?
Kilowatts: real power in thousands of watts, often shown as kW on equipment data. Voltage: the supply voltage used by the load, such as 48 V DC, 120 V, 240 V, 208 V, or 480 V. Phase: DC, single-phase AC, or three-phase AC formula selection. Power factor: AC correction factor between 0 and 1 for real power versus apparent power. Efficiency: the percent of input power that becomes useful output power; lower efficiency raises estimated input watts and amps.
How should I read the Kilowatts to Amps Calculator answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
What should I double-check before trusting the answer?
This is a simplified electrical estimate for planning and comparison. Breaker size, conductor size, voltage drop, duty cycle, motor starting current, local code, and equipment-nameplate rules still need manufacturer data and qualified electrical review. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
What is the kW to amps formula?
First convert kW to watts, then adjust for efficiency when needed. For DC, divide input watts by volts. For single-phase AC, divide by volts times power factor. For three-phase AC, divide by volts times sqrt(3) times power factor.
Why does the calculator ask for efficiency?
If the kW value describes output power, the equipment may need more input power because of losses. For example, 5 kW at 90% efficiency uses about 5,555.56 input watts before the current calculation.
Related tools
- Watts to Amps Calculator Convert watts to amps with voltage, phase type, and power factor.
- kVA to Amps Calculator Convert apparent power in kVA to amps for single-phase or three-phase systems.
- Electricity Calculator Estimate electricity use and cost from watts, hours, days, and rate per kWh.
Keep exploring
If this guide is close but not exact, these links keep you near the same kind of problem.
- Calculators Browse the full category for related tools that help with the same job.
- All free tools Search the complete Access Free Tools library by task, category, or tool name.
- All calculator and utility guides Find more plain-language examples, formulas, mistakes, and result explanations.
- Free calculator resources Start here when you are not sure which calculator page fits.
Privacy and copying results
Recent answers stay visible only while you work in the current browser tab. They are not sent to a server.
Use Copy answer when you want to save the inputs and result in notes, homework, a message, or a project list. Check the units, labels, and limits before copying.