Amps to Watts Calculator

Use this free amps to watts calculator to estimate power from current, voltage, phase type, and power factor.

Research-backed assumptions Formula steps Examples included Private in-browser use

AmpsCurrent draw in amps.VoltsSupply voltage for the circuit or device.Phase / current typeChoose DC, single-phase AC, or three-phase AC.Power factorUse 1 for DC/resistive loads. Motors and many AC devices may be lower, such as 0.8 or 0.9.

Estimated power1500 W

12.5 A at 120 V

Kilowatts: 1.5 kW
Phase factor: 1
Power factor: 1

This is a simplified electrical estimate. Use rated equipment data and qualified advice before sizing circuits or parts.

Formula steps

Choose the formula based on DC, single-phase AC, or three-phase AC.
Multiply amps by volts, phase factor, and power factor.
Divide watts by 1,000 to show kilowatts too.

How to use the amps to watts calculator

Enter amps, volts, phase/current type, and power factor.
Press Calculate watts to estimate real power.
Read the kilowatt metric when you need a larger power unit.
Use rated equipment data for real sizing instead of guessing power factor.

Common uses

Estimate watts from a current draw.

Convert a circuit amp value into rough power.

Compare single-phase and three-phase examples.

Understand when power factor changes AC watts.

Examples

120 V load 12.5 A, 120 V, PF 1

1,500 W

Single-phase AC 10 A, 240 V, PF 0.9

2,160 W

Three-phase AC 20 A, 208 V, PF 0.85

About 6,124 W

Frequently asked questions

Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.

When should I use the Amps to Watts Calculator?

Use it when your task matches one of these common needs: Estimate watts from a current draw. Convert a circuit amp value into rough power. It works best when you already know the values, dates, units, or settings the page asks for.

What is the Amps to Watts Calculator doing with my inputs?

In plain language: The calculator multiplies amps by volts for DC/single-phase loads, or by volts x sqrt(3) for three-phase loads, then includes power factor. The examples on the page are there so you can compare your inputs with a filled-out calculation before copying the answer.

What do the main Amps to Watts Calculator inputs mean?

Amps: current drawn by the device or circuit. Volts: supply voltage. Phase: DC, single-phase AC, or three-phase AC formula selection. Power factor: AC correction factor used to estimate real watts.

How should I read the Amps to Watts Calculator answer?

Read the main answer first, 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. Use rated equipment data and qualified advice before sizing circuits or parts. Also check that you used the right unit, date, scale, or mode because small input changes can change the result.

Is amps to watts always amps times volts?

For DC and simple single-phase estimates, watts are amps times volts, then power factor for AC. Three-phase estimates also multiply by the square root of 3.

Why does the same amperage give different watts?

Voltage, phase, and power factor all change the answer. Ten amps at 12 volts is very different from ten amps at 240 volts or 480 volt three-phase service.

Does the site save what I enter?

No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.