1500 W at 120 V
- Phase factor
- 1
- Power factor
- 1
- Power
- 1500 W
This is formula math only. Real electrical loads need correct voltage, power factor, breaker, wire, code, and professional review.
Watts to Amps Calculator
Use this free watts to amps calculator to estimate current draw from real power, supply 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 voltage by the phase factor and power factor.
- Divide watts by that adjusted voltage value to estimate amps.
How to use the Watts to Amps Calculator
- Enter watts, volts, phase/current type, and power factor.
- Press Calculate amps to estimate current draw.
- Use power factor 1 only when the load is DC or a simple resistive AC load.
- Check equipment nameplates, breakers, wiring, and code before real electrical work.
What people use it for
Estimate current from a device watt rating.
Compare 12 V DC, 120 V single-phase, 240 V single-phase, and 208 V three-phase examples.
Understand why AC power factor changes the amp estimate.
Check rough load math before using detailed tools such as voltage drop or Ohm's law.
Read appliance or equipment labels more carefully before asking for qualified electrical help.
Quick examples
120 V heater
1,500 W, 120 V, power factor 112.5 A
Single-phase motor
2,200 W, 240 V, PF 0.9About 10.19 A
Three-phase load
5,000 W, 208 V, PF 0.85About 16.34 A
12 V DC device
60 W, 12 V, PF 15 A
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 Watts to Amps Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Calculators Browse related calculators and utilities in the same category.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
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 Watts to Amps Calculator?
Use it when your task matches one of these common needs: Estimate current from a device watt rating. Compare 12 V DC, 120 V single-phase, 240 V single-phase, and 208 V three-phase examples. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Watts to Amps Calculator doing with my inputs?
In plain language: For DC and single-phase AC, amps = watts / (volts x power factor). For three-phase AC, amps = watts / (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 Watts to Amps Calculator inputs mean?
Watts: real power used by the device or load. Volts: the supply voltage feeding the load. Phase: DC, single-phase AC, or three-phase AC changes the current formula. Power factor: how efficiently AC current becomes real power. Use 1 for DC or resistive loads.
How should I read the Watts to Amps 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 formula math for learning and planning. Real electrical work needs the equipment nameplate, correct voltage, power factor, breaker, wire, code rules, and qualified review. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
Why does power factor matter?
Power factor matters for AC loads because not every amp becomes useful real power. A motor with 0.8 power factor needs more current than a resistive load using the same watts and volts.
Can I use this to choose a breaker size?
No. This helps you understand the math, but breaker and wire choices need code rules, equipment instructions, continuous-load rules, temperature, and qualified electrical review.
What formula should I use for three-phase watts to amps?
Use amps = watts / (volts x 1.732 x power factor). The 1.732 is the square root of 3, which is part of the three-phase power formula.
Should I use rated watts or starting watts?
Use the value that matches your question. Rated watts estimate normal running current. Starting watts or motor inrush can be much higher, so do not use this simple result as a final safety decision.
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.
Related tools
Amps to Watts Calculator Convert amps to watts for DC, single-phase AC, and three-phase AC loads. Open Voltage Drop Calculator Estimate voltage drop from current, wire length, voltage, phase, and copper AWG size. Open Ohms Law Calculator Solve voltage, current, resistance, and power from two known circuit values. Open Electricity Calculator Estimate electricity use and cost from watts, hours, days, and rate per kWh. Open