Electric Potential converter

The volt (V) is the reference unit for electric potential, and every other unit on this page is a decimal multiple or submultiple of it: a kilovolt (kV) is 1,000 V, a megavolt (MV) is 1,000,000 V, a millivolt (mV) is 0.001 V, a microvolt (µV) is 0.000001 V, and a nanovolt (nV) is a billionth of a volt. The abvolt (abV), from the old electromagnetic CGS system, is a tiny 1e-8 V, while the statvolt (statV), from the electrostatic CGS system, is a comparatively large 299.792458 V — a number tied to the speed of light in that older unit framework. The watt per ampere (W/A) isn't a scaled unit at all; by Ohm's law and power relationships it works out to be exactly one volt, just named for the ratio of power to current instead of potential to charge.

The page's featured pair converts millivolt to volt with V = mV × 0.001, and the reverse multiplies by 1,000. Because "milli" always means one-thousandth, this is the same relationship you'd use for any milli-to-base conversion in the metric system.

A multimeter reading of 250 mV across a sensor converts to 250 × 0.001 = 0.25 V. A car battery rated at 12.6 V converts up to 12,600 mV if you need the finer-grained unit, and a microcontroller's 3.3 V logic rail equals 3,300,000 µV when expressed in microvolts — a scale more familiar to people measuring tiny signal levels.

Volts and their multiples cover an enormous practical range. Biosensors and EEG electrodes pick up brain and muscle signals in the microvolt to millivolt range, household electronics run on single-digit to low-double-digit volts, automotive and solar systems sit in the tens of volts, and long-distance power transmission lines operate at hundreds of kilovolts specifically to push large amounts of power through a line with lower current and therefore lower resistive losses. Precision voltage references used to calibrate lab instruments are often specified to the microvolt level of stability.

A frequent point of confusion is mixing up millivolt and microvolt readings, since both start with "m" when abbreviated carelessly (mV vs µV) — a thousand-fold error that matters a great deal in sensitive instrumentation. Another is forgetting that statvolt and abvolt come from an entirely different, now-obsolete unit system (CGS) rather than being SI prefixes, so their conversion factors look unusually precise rather than being round powers of ten.

It also helps to remember that "potential" is always a difference between two points, even when only one number is quoted. Saying a point is "at 5 V" is shorthand for "5 V higher than whatever reference point, usually ground, was chosen as zero" — the same physical setup can be described with completely different absolute numbers depending on where that zero is placed, which is why some automotive and electronics diagrams explicitly label their reference or "common" point before any voltage on the schematic means anything.

Battery and cell specifications add a further wrinkle worth knowing: a "12-volt" lead-acid car battery is actually a nominal label for six 2.1 V cells in series, and its real resting voltage when fully charged is closer to 12.6-12.8 V, not exactly 12 V. The nominal figure is a convenient round name for the battery family rather than a precise measurement, a pattern that repeats across almost every battery chemistry from alkaline cells to lithium-ion packs.