About the Volts to Watts Calculator
This calculator converts V to W. V is volts, the electrical pressure that pushes the current, and W is one joule of energy per second, the basic unit of power printed on bulbs, chargers and appliances. It multiplies the voltage by the current and, for AC, by the power factor and by √3 when the supply is three-phase. Enter your figures and the answer appears at once, together with a few related values, and you can copy the result with one tap. The sums are done in your browser and nothing is sent anywhere.
Updated October 2026
How to use the Volts to Watts Calculator
- 1Enter the value in V.
- 2Fill in the other boxes that the V to W calculation needs, such as time, voltage or power factor.
- 3Read the answer in the large result box.
- 4Check the extra rows for related values.
- 5Press Copy result to keep it.
When you need V to W
Volts alone cannot be converted into watts, because power depends on the current as well. This calculator takes both and gives the real power. It suits a car accessory on 12 V, a charger, an LED strip or a motor on mains, and it handles three-phase supplies by using the line voltage.
Choose DC for batteries and plug-in adapters. Choose single-phase AC for household appliances, with a power factor close to 1 for heaters and nearer 0.8 for motors. Choose three-phase AC for industrial machines, with the voltage measured between two lines.
How the V to W sum works
Watts = volts × amps for DC, × power factor for single-phase AC, and × √3 × power factor for three-phase AC. For 12 V DC at 5 A the power is 12 × 5 = 60 W.
The displayed answer is rounded to six significant figures, but the sum itself is not rounded, so converting V to W and back again gives you the number you started with.
- DC: V × A
- Single-phase AC: V × A × PF
- Three-phase AC: √3 × V × A × PF
Mistakes to avoid when converting V to W
The usual error is to leave out the power factor on AC loads, which makes the power look too high. Another is using the phase voltage in a three-phase sum instead of the line voltage. Check the rating plate for the current and power factor.
On phone and computer
On a phone, type in the boxes one after another and read the W result underneath; the Copy button puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the W value move. The V to W page works the same on both. Reverse the step with Watts to Volts Calculator or use Amps to Watts Calculator if you start from current. Ohm's Law Calculator links all values together, and Watts, Amps and Volts Calculator shows all three at once.
Features
- V to W in one step
- Related values shown with the answer
- Clear messages for impossible inputs
- Copy the result with one tap
- Private: nothing is uploaded
- Works on phone and computer
Frequently asked questions
How do I convert V to W?
Watts = volts × amps for DC, × power factor for single-phase AC, and × √3 × power factor for three-phase AC. For 12 V DC at 5 A the power is 12 × 5 = 60 W.
What is the formula for V to W?
Watts = volts × amps for DC, × power factor for single-phase AC, and × √3 × power factor for three-phase AC. The calculator applies it exactly and rounds only the displayed answer.
What is the difference between V and W?
V is volts, the electrical pressure that pushes the current. W is one joule of energy per second, the basic unit of power printed on bulbs, chargers and appliances. They measure different things, which is why converting from V to W needs more than a simple multiplication in some cases.
Can I convert volts to watts without amps?
No. You need the current or the resistance as well. If you know the resistance, find the current first with Ohm's law, then use this calculator.
What power factor should I use?
Use 1 for DC, and for resistive loads such as heaters and kettles. Use about 0.8 to 0.9 for motors and many appliances, or the value on the rating plate.
Is this V to W calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so the figures you type are not uploaded or stored. It is meant for planning and learning; for wiring or safety work, check the result against your equipment's rating plate and local rules.