About the kW to Volts Calculator
Kilowatts can't be turned into volts on their own; you also need the current. This calculator divides the power by the current, and for AC also by the power factor and, on three-phase supplies, by √3. That gives the voltage that delivers the stated power at the stated current. It is handy for checking whether a heater, charger or motor is meant for 120 V, 230 V or 400 V, or for working backwards from measured power and current. Choose the supply, type the figures and the voltage appears at once.
Updated October 2026
How to use the kW to Volts Calculator
- 1Pick DC, single-phase AC or three-phase AC.
- 2Enter the power in kilowatts.
- 3Enter the current in amps.
- 4For AC, enter the power factor (1 for heaters, about 0.85 for motors).
- 5Read the voltage; for three-phase it is the line-to-line voltage.
Why you need amps as well
Power is voltage times current. Knowing only the kilowatts leaves one unknown too many, which is why the calculator asks for the current. With both, it can give the single voltage that fits. If you only have the resistance, find the current first with Ohm's law, then come back here.
The formulas used
The displayed answer is rounded to six significant figures, but the working is not rounded, so you can convert back with our Volts to kW calculator and get the original power.
- DC: V = 1,000 × P(kW) ÷ I
- Single-phase AC: V = 1,000 × P ÷ (I × PF)
- Three-phase AC: V = 1,000 × P ÷ (√3 × I × PF)
Practical examples
An EV charger delivering 7.2 kW at 32 A works out at 225 V on single phase. A 22 kW charger at 32 A per phase on three-phase gives about 397 V line to line. A 1.2 kW load on a 12 V battery would draw 100 A, which is why big inverters use 24 V or 48 V systems instead.
Phone and computer
Every input has a clear label and a large touch area, so the calculator is easy to use on a phone. On a computer the result sits next to the inputs. All the sums run locally in your browser. Voltage from power needs the current too, so check that value. Find current with the kW to Amps Calculator, the other direction with the Volts to kW Calculator, and test a simple circuit with the Ohm's Law Calculator.
Features
- kW and amps to volts
- DC, single-phase and three-phase
- Power factor for AC loads
- Line-to-line voltage for three-phase
- Copy the answer with one tap
- Works offline once the page has loaded
Frequently asked questions
How do I convert kW to volts?
Divide the watts by the amps. For DC: V = 1,000 × kW ÷ A. For single-phase AC: V = 1,000 × kW ÷ (A × PF). For three-phase AC: V = 1,000 × kW ÷ (√3 × A × PF).
Can I convert kW to volts without the current?
No. The same power can be delivered at a low voltage with a high current or a high voltage with a low current, so you need one more figure, the current or the resistance.
What voltage is a 3 kW heater at 13 A?
3,000 ÷ 13 ≈ 231 V, which is a standard UK or European single-phase supply.
What does the three-phase result mean?
It is the line-to-line voltage, measured between two phases. For a 400 V system the phase-to-neutral voltage is about 230 V.
Which power factor should I enter?
1 for resistive loads such as heaters and ovens, around 0.85 for motors and pumps, or the value on the rating plate if it shows cos φ.
Why is my answer lower than the mains voltage?
Usually because the current you used is the fuse or breaker rating rather than the running current, or the power is the output power of a motor rather than its input power.