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.
Amps to Watts Calculator
Use this free amps to watts calculator to estimate real power from current, voltage, phase type, and power factor.
Inputs explained Result checks Example values Runs in your browser
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.
What people use it for
Estimate watts from a current draw.
Convert a circuit amp value into rough power.
Compare single-phase and three-phase examples.
Understand when voltage, phase, or power factor changes AC watts.
Quick examples
120 V space heater
12.5 A x 120 V x PF 11,500 W, or 1.5 kW
Single-phase motor estimate
10 A x 240 V x PF 0.92,160 W, or 2.16 kW
Three-phase shop load
20 A x 208 V x sqrt(3) x PF 0.85About 6,124 W, or 6.12 kW
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Amps to Watts Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
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- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
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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 measurements, amounts, units, or options the page asks for.
What is the Amps to Watts Calculator doing with my inputs?
In plain language: DC watts = amps x volts. Single-phase AC watts = amps x volts x power factor. Three-phase AC watts = amps x volts x sqrt(3) x power factor. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Amps to Watts Calculator inputs mean?
Amps: current drawn by the device or circuit, usually from a nameplate, meter, or specification. Volts: the supply voltage used by the load, such as 12 V DC, 120 V, 240 V, 208 V, or 480 V. Phase: DC, single-phase AC, or three-phase AC formula selection. Power factor: AC correction factor used to estimate real watts from apparent volt-amps.
How should I read the Amps to Watts Calculator answer?
Read the headline answer, 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 for planning and comparison. Starting surge, code rules, conductor size, breaker size, duty cycle, and equipment nameplate limits still need manufacturer data and qualified electrical review. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
Is amps to watts always amps times volts?
For DC, watts are amps times volts. For single-phase AC, multiply amps by volts and power factor. For three-phase AC, 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.
What power factor should I enter?
Use the power factor from the equipment nameplate or specification when you have it. If you do not know it, 1 is only a best-case estimate for AC loads and can overstate real-world power for motors and similar equipment.
Can I size a breaker or wire from this result?
No. Use this as planning math only. Breaker, conductor, extension-cord, motor, and appliance sizing depends on code rules, starting current, duty cycle, temperature, and equipment instructions.
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.
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