Amps to Watts Calculator
Convert amps to watts for DC, single-phase and three-phase AC, with power factor applied.
Power factor is why AC needs an extra term
In a DC circuit, watts are simply amps times volts. In AC, current and voltage can fall out of step, so some of the current does no useful work. Power factor is the fraction that does: resistive loads such as heaters sit at 1.0, motors typically run 0.8–0.9, and older fluorescent ballasts can drop below 0.6. Ignoring it overstates real power by exactly that fraction.
The formula
DC: W = A × V · AC single phase: W = A × V × PF · Three phase: W = √3 × A × V × PF
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Amps to Watts Calculator
- Fill in each field with your own figures — the defaults are only there as an example.
- The result updates as you type, so there is no button to press.
- Check the breakdown under the main result for the supporting numbers.
- Use the copy button to take the result with you, or share the link to reload the same inputs.
Amps to Watts Calculator — frequently asked questions
Is this amps to watts calculator free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
How accurate is the result?
The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.
Can I use it on my phone?
Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.
Focused versions of this calculator
Each of these does one specific job with its own defaults and explanation.
- Three Phase Amps to Watts Calculator Three-phase power with the √3 factor and power factor applied.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the amps to watts calculator.
- w calculator
- w calculator pc
- calculator v in w
- w=pt formula
About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 15, 2026 · Calculation runs client-side · No data collected · Report an error