Enter a value in any field to convert between all units
Convert between any two voltage units
See the relative magnitude of different voltage units
Note: The meter shows relative magnitude on a logarithmic scale from pV to PV.
Compare different voltage magnitudes across common applications
| Voltage Range | Example Applications |
|---|---|
| 1 pV - 1 nV | Quantum electronics, ultra-sensitive measurements |
| 1 nV - 1 μV | Sensitive scientific instruments, thermal noise |
| 1 μV - 1 mV | Microphone signals, thermocouple outputs |
| 1 mV - 100 mV | Sensor outputs, audio signals |
| 100 mV - 10 V | Batteries, digital electronics, microcontrollers |
| 10 V - 1 kV | Household electronics, automotive systems |
| 1 kV - 100 kV | Industrial equipment, X-ray machines |
| 100 kV - 1 MV | High-voltage transmission, particle accelerators |
| > 1 MV | Lightning strikes, nuclear research |
Voltage is the electric potential difference between two points in a circuit. The SI unit of voltage is the volt (V), which is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power.
The volt is named after the Italian physicist Alessandro Volta, who invented the first chemical battery. For practical applications, we use various multiples and submultiples of the volt:
To convert between voltage units, you simply multiply or divide by powers of 10:
| From | To | Multiply By |
|---|---|---|
| Volts (V) | Millivolts (mV) | 1,000 |
| Volts (V) | Microvolts (μV) | 1,000,000 |
| Volts (V) | Kilovolts (kV) | 0.001 |
| Millivolts (mV) | Volts (V) | 0.001 |
| Kilovolts (kV) | Volts (V) | 1,000 |
| Megavolts (MV) | Kilovolts (kV) | 1,000 |
To learn more about voltage and electrical concepts, check out these resources:
Voltage in practice spans about twelve orders of magnitude, and each decade belongs to a different kind of engineering.
One practical note: a measurement is only as good as its reference. At microvolt levels the voltage drop along a ground trace carrying other circuits’ return current is itself millivolts, which is why sensitive measurements use a separate sense return rather than sharing a ground plane path.
| Prefix | Symbol | Factor |
|---|---|---|
| pico | p | 10−12 |
| nano | n | 10−9 |
| micro | µ | 10−6 |
| milli | m | 10−3 |
| kilo | k | 103 |
| mega | M | 106 |
| giga | G | 109 |
Two conventions cause real errors. Case matters: m is milli and M is mega, a factor of a billion apart, so writing mW when MW is meant is not a typo anyone can shrug off. And µ is frequently written as u because it is easier to type — 10uF and 10µF mean the same thing, and the substitution is universal enough in datasheets and schematics to be treated as standard.
Engineering notation — exponents restricted to multiples of three — exists precisely so that every value maps onto a prefix. It is why components are specified as 4.7 kΩ rather than 0.0047 MΩ, and why keeping values in that form makes mental arithmetic and cross-checking far easier.
Anything above roughly 50 V AC or 120 V DC is generally treated as hazardous and attracts insulation, creepage and clearance requirements. Below that, the main risks are burns and arc energy rather than shock.
Mainly from thermal EMFs at junctions of dissimilar metals and from amplifier offset drift, both of which vary with temperature and can exceed the signal itself.
m is milli, meaning one thousandth, and M is mega, meaning one million. They differ by a factor of a billion, so case must be written carefully.
Because µ is awkward to type on many keyboards and did not survive older character encodings. Writing 10uF for 10µF is standard practice in datasheets and schematics.
Scientific notation restricted to exponents that are multiples of three, so that every value corresponds to an SI prefix. It is why components are quoted as 4.7 kΩ rather than 0.0047 MΩ.