Watts to Amps Calculator
Convert electrical power in watts to current in amps for DC, single-phase or three-phase systems.
Interactive Electrical Calculator
Watts to Amps Calculator
Convert electrical power in watts to current in amps for DC, single-phase or three-phase systems.
Result
Enter values and calculate.
About the Watts to Amps Calculator
Use the Watts to Amps Calculator below to work through converting between watts, amps, volts, kW, kVA and VA in seconds, right in your browser. Convert electrical power in watts to current in amps for DC, single-phase or three-phase systems. Getting a conversion wrong by even a small factor can lead to an oversized bill of materials or, worse, a breaker or cable that is undersized for the real current.
It's built for electricians sizing breakers and cable, solar and generator installers matching equipment ratings, and anyone reading a nameplate that lists one unit when they need another, and every field updates instantly so you can try a few scenarios before committing to a real installation.
How the calculation works
Here is the relationship the calculator solves for you:
I = P / (V × PF) for single phase; I = P / (√3 × V × PF) for three phase.
Where each input maps to a field in the calculator above:
- Power in W.
- Voltage in V.
- Power Factor.
- System — choose between DC, Single Phase, Three Phase.
Change any field above and the result recalculates immediately — nothing is submitted anywhere, so it's safe to experiment freely.
A worked example
For example, start with 1000 W for power, 230 V for voltage and 1 for power factor. Those defaults are only a starting point — replace them with your own measured or nameplate values, then press Calculate to get a result specific to your situation.
When to use the Watts to Amps Calculator
Typical reasons people reach for the Watts to Amps Calculator:
- Converting a nameplate wattage to the amp draw needed to size a breaker or extension cord.
- Turning a generator or UPS kVA rating into the real kW load it can actually support.
- Checking a utility bill or inverter spec sheet that mixes kW, kWh and kVA.
- Working out current draw for a three-phase motor or panel from its power rating.
Good practice: Always check whether the source rating is real power (W/kW) or apparent power (VA/kVA) before converting — they are only equal when power factor is exactly 1.
Also worth knowing: Three-phase conversions use a √3 factor that single-phase and DC calculations do not, so double check which system you are working with.
Frequently asked questions
What does the Watts to Amps Calculator calculate?
Convert electrical power in watts to current in amps for DC, single-phase or three-phase systems.
How accurate is this calculator?
The formula above is applied exactly to the values you enter, so the math itself is precise. Real-world results can still differ due to component tolerances, temperature, installation method, equipment efficiency and local code requirements, so treat the output as a strong planning estimate and verify final designs against manufacturer data and the electrical code that applies to your installation.
Is this calculator free to use?
Yes. The Watts to Amps Calculator is completely free, with no account, download or installation required.
Why does this calculation matter in practice?
Power factor and phase count both change the relationship between watts, volt-amps and current, which is where most manual conversion mistakes happen.
Will this work for both metric and everyday values?
The Watts to Amps Calculator works on any modern browser, phone or desktop, and recalculates as soon as you press Calculate. If a result looks off, double-check that every field is filled in with the unit shown next to it (mixing up units, such as W with kW, is the most common cause of an unexpected answer) and re-enter the values.