🔋 Voltage

Voltage Converter

Sensor signals in microvolts, batteries in volts, transmission lines in kilovolts — convert electrical potential difference. Enter a value and press Convert.

Written and reviewed by SM Arijul Islam · Last reviewed 28 October 2026 · Editorial standards · Report an error

About the voltage converter

Voltage measures the electrical potential difference that drives current through a circuit, one volt being one joule per coulomb. Mains supplies around the world are either roughly 230 V (Europe, most of Asia and Africa) or 120 V (North America, parts of South America and Japan).

Factors used

1 V = 1,000 mV = 1,000,000 µV
1 kV = 1,000 V · 1 MV = 1,000,000 V
1 abvolt = 10⁻⁸ V
1 statvolt ≈ 299.792458 V
Power (W) = voltage (V) × current (A)

Never work on live mains circuits. Verify supply voltage with a rated meter before connecting equipment.

How to convert voltage

Voltage, or potential difference, is the electrical pressure that drives current around a circuit, measured in volts (V). One volt delivers one joule of energy per coulomb of charge. Metric prefixes scale it from microvolts in sensors up to kilovolts in transmission lines. Voltage is measured across two points in a circuit, which is the key difference from current, which is measured through it.

Common voltage conversions

One volt expressed in other units of voltage
Unit	1 volt equals
Microvolt (µV)	1,000,000
Millivolt (mV)	1,000
Kilovolt (kV)	0.001
Gigavolt (GV)	0.000000001

Everyday uses

Battery, charger and power-supply specs
Mains supply and appliance ratings
Electronics, sensors and microcontrollers
Understanding wattage ratings
Insulation and electrical safety checks

Frequently asked questions

What voltage is mains electricity?

Commonly 230 V in Europe and much of the world, and 120 V in North America. Both are alternating current.

How many volts are in a kilovolt?

1,000. A millivolt is one thousandth of a volt and a microvolt one millionth.

Is a higher voltage always more dangerous?

Voltage drives current through the body, so higher voltages are generally more hazardous, but the current path and duration matter just as much.

What is the difference between AC and DC?

Alternating current reverses direction periodically, like a wall socket; direct current flows one way, like a battery.

More worked examples

A 12 V battery delivering 2 A provides 24 W of power.
Five volts across a 220 ohm resistor gives a current of about 22.7 mA.
A 230 V circuit rated at 10 A can supply up to 2,300 W.
A 10,000 mAh power bank rated at 3.7 V stores about 37 watt-hours.

Quick reference

Common voltage relationships and their equivalents
Situation	Equivalent
1 volt	1 watt per ampere
1 millivolt	0.001 volts
1 kilovolt	1,000 volts
1,000 mAh at 3.7 V	3.7 Wh
10,000 mAh at 5 V	50 Wh
1 watt-hour	1 volt × 1 amp-hour

Common mistakes to avoid

Confusing volts with watts. Voltage alone tells you nothing about power until you also know the current.
Reading a power bank's mAh rating as an energy figure. Without the voltage it is only a charge figure, and the marketing number is often quoted at the cell voltage, not the output voltage.
Ignoring voltage drop over long cable runs, which can be significant at low voltages and high currents.
Treating alternating and direct voltages as directly comparable. Mains ratings are RMS, while peak values are about 1.41 times higher.

Further questions

What is a volt?

One joule per coulomb, or the potential difference that drives one ampere through a resistance of one ohm.

How do I convert mAh to watt-hours?

Divide the milliamp-hours by 1,000 to get amp-hours, then multiply by the voltage. So 10,000 mAh at 5 V is 10 Ah × 5 V = 50 Wh.

What is the difference between RMS and peak AC voltage?

Peak is about 1.414 times RMS. A 230 V RMS mains supply peaks near 325 V.

Why do phone chargers list several voltages?

Modern fast charging negotiates a voltage, so a charger may offer 5 V, 9 V, 15 V or 20 V and the phone picks one to reach the power it wants.

Sources and standards

The volt is a derived SI unit, one watt per ampere, realised through the Josephson effect with the Planck constant fixed. NIST SP 811 lists the derived-unit relationships used here, and the page warns that RMS, peak and peak-to-peak values are not interchangeable.