About the Watts to Volts Calculator
This calculator converts W to V. W is one joule of energy per second, the basic unit of power printed on bulbs, chargers and appliances, and V is volts, the electrical pressure that pushes the current. It divides the power by the current, and for AC loads it also divides by the power factor, and by √3 for a three-phase supply. 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 Watts to Volts Calculator
- 1Enter the value in W.
- 2Fill in the other boxes that the W to V 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 W to V
Sometimes you know how much power a device uses and how much current it draws, but not the supply voltage. Dividing the power by the current gives the voltage. It helps when you identify an unlabelled adapter, check a battery bank, or test a calculation against a rating plate.
Technicians also use it to confirm that a measured current and a stated power agree with the voltage that should be present. If the sum gives 12 V but the supply is 24 V, one of the readings is wrong or the device is not running at full load.
How the W to V sum works
Volts = watts ÷ amps for DC. For AC divide by the power factor too, and by √3 for three-phase. A 60 W load drawing 5 A on a DC supply is running at 60 ÷ 5 = 12 V.
The displayed answer is rounded to six significant figures, but the sum itself is not rounded, so converting W to V and back again gives you the number you started with.
- DC: W ÷ A
- AC: W ÷ (A × PF)
- Three-phase: W ÷ (√3 × A × PF)
Mistakes to avoid when converting W to V
Do not use this for a device whose power and current were measured at different loads, since the answer would mean nothing. On AC supplies, include the power factor, otherwise the voltage will be too low. For three-phase supplies the result is the line-to-line voltage.
On phone and computer
On a phone, type in the boxes one after another and read the V 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 V value move. The W to V page works the same on both. Amps to Volts Calculator uses current instead of resistance, Volts to Watts Calculator reverses the step, and Watts to Amps Calculator gives the current. Ohm's Law Calculator ties them together.
Features
- W to V 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 W to V?
Volts = watts ÷ amps for DC. For AC divide by the power factor too, and by √3 for three-phase. A 60 W load drawing 5 A on a DC supply is running at 60 ÷ 5 = 12 V.
What is the formula for W to V?
Volts = watts ÷ amps for DC. For AC divide by the power factor too, and by √3 for three-phase. The calculator applies it exactly and rounds only the displayed answer.
What is the difference between W and V?
W is one joule of energy per second, the basic unit of power printed on bulbs, chargers and appliances. V is volts, the electrical pressure that pushes the current. They measure different things, which is why converting from W to V needs more than a simple multiplication in some cases.
Can I find volts from watts alone?
No. A watt rating does not fix the voltage; the same power can come from low volts and high amps or the other way round. You need the current as well.
What if the power factor is unknown?
For a resistive load use 1. For a motor or a mixed load use 0.8 to 0.9 as a rough value, but use the figure from the rating plate when you have it.
Is this W to V 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.