Three Phase Watts to Amps Calculator
Three-phase power with the √3 factor and power factor applied.
How this differs from the general calculator
Three-phase power introduces a √3 factor because the three windings are 120° out of phase: W = √3 × A × V × PF. Using the single-phase formula on a three-phase supply understates power by about 42%.
The 80% rule
Continuous loads — anything running for three hours or more — should not exceed 80% of a breaker's rating under the NEC. A 15 A circuit therefore carries 12 A continuously, or about 1,440 W at 120 V. That is why a 1,500 W space heater trips a shared kitchen circuit: the heater alone is at the limit before anything else is plugged in.
How to use the Three Phase Watts to Amps 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.
Three Phase Watts to Amps Calculator — frequently asked questions
Is this three phase watts to amps 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.
This page is a focused version of the Watts to Amps Calculator, which handles every variation in one place.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the three phase watts to amps calculator.
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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