Amps to Watts Calculator
This amps to watts calculator converts amps to watts and watts to amps for DC, single-phase, and three-phase AC. Enter the current or power with the voltage, and the amps to watts calculator returns the answer using volts and amps, with the power factor for AC loads.
Results
The Amps to Watts Calculator is part of our AC & Three Phase collection. Browse more ac & three phase to size, convert, and check your work alongside this tool.
What the amps to watts calculator does
The amps to watts calculator converts between current and power. Amps measure the flow of current and watts measure the power used, so to convert amps to watts you also need the voltage, and for AC the power factor. This amp to watt conversion calculator works both ways, so the same tool answers watts to amps and w to amps questions, from volts and amps, for DC, single-phase, and three-phase.
Amps to watts formula
The amps to watts formula depends on the current type:
To go from watts to amps, the amps to watts calculator rearranges these, so w to amps is simply power divided by voltage (times power factor for AC). That is how one amp to watt conversion calculator covers both directions.
Amps to watts conversion example
A single-phase motor drawing 10 amps at 230 volts with a 0.9 power factor:
Reverse it and the watts to amps conversion of 2070 W at the same volts and amps returns 10 amps, confirming the wattage from volts and amps both ways.
How to use the amps to watts calculator
Choose the current type, then enter the current and voltage to convert amps to watts. For the reverse, enter watts and voltage and the amps to watts calculator gives watts to amps. Add the power factor for AC. Working from wattage from volts and amps takes seconds, and for three-phase you enter the line-to-line voltage.
Reading the amps to watts result
The watts figure is real power, the energy your load uses and the number your meter records. Use it to estimate running cost or size a generator. When you convert amps to watts on AC, ignoring the power factor overstates power, so the amps to watts calculator includes it. The reverse w to amps result sets your fuse, breaker, and cable size.
When to use the amps to watts calculator
- Converting amps to watts to estimate energy cost
- Running a watts to amps conversion to size a fuse or cable
- Finding wattage from volts and amps for an appliance
- Sizing a generator with an amp to watt conversion calculator
Common amps to watts conversion mistakes
- Skipping power factor on AC. The AC amps to watts conversion needs it, or you misstate power.
- Phase voltage for three-phase. Use line-to-line volts and amps in the calculator.
- Confusing watts with VA. The amps to watts calculator gives real power; apparent power is higher.
Tips for accurate amps to watts results
- Read the nameplate for voltage and power factor before you convert amps to watts.
- Use line-to-line voltage for every three-phase w to amps conversion.
- Divide watts by 1000 for kilowatts to estimate energy cost.
Why AC changes the amps to watts conversion
The amps to watts calculator treats DC and AC differently for a real reason. In DC, voltage and current are steady and in step, so to convert amps to watts you just multiply. In AC with motors or transformers the current lags the voltage, and during part of each cycle energy flows backward instead of doing work. The power factor in the AC amps to watts formula captures that loss, which is why converting amps to watts without it, or doing a bare w to amps division, overstates or understates the true figure.
Wattage from volts and amps in three-phase
The three-phase amps to watts conversion includes the square root of three because power is delivered across three conductors offset by 120 degrees. The result is that wattage from volts and amps in three-phase is much higher for the same current than single-phase. This is why the amp to watt conversion calculator asks you to pick the phase first, and why a three-phase w to amps conversion returns a smaller current for the same power. Understanding this keeps your fuse and cable sizing safe.
Reference Table
| Current type | Amps to watts formula |
|---|---|
| DC | P = V × I |
| AC 1-phase | P = V × I × PF |
| AC 3-phase | P = √3 × V × I × PF |
Amps to Watts Calculator FAQ
How do I convert amps to watts?
Multiply volts by amps, and by the power factor for AC. So wattage from volts and amps is P = V × I × PF. The amps to watts calculator does it and reverses to watts to amps too.
How do I convert watts to amps?
Divide watts by volts (and by the power factor for AC). This w to amps conversion is the reverse of amps to watts, and the amp to watt conversion calculator handles both directions.
How many watts is one amp?
It depends on voltage. At 230 volts, one amp is 230 watts. You cannot convert amps to watts without the voltage, which is why the calculator asks for volts and amps together.
Do I need the power factor?
For DC no, for AC yes. The power factor corrects the AC amps to watts conversion for the phase difference. Use 1.0 for heaters and 0.7 to 0.9 for motors.