Hong Life CalculatorsUnderstanding the voltage converter — concept and principle
Voltages in everyday and technical work span an enormous range: sensor and audio signals in microvolts and millivolts, batteries and household supplies in volts, and power lines in kilovolts. This converter moves a value between µV, mV, V, kV and MV and shows every unit at once, which helps when reading datasheets, setting a multimeter range, or checking a calculation that mixes prefixes.
How it is calculated
Each unit is stored as a number of volts: result = value × V(from) ÷ V(to).
- 1 µV = 10⁻⁶ V
- 1 mV = 10⁻³ V
- 1 kV = 10³ V
- 1 MV = 10⁶ V
Because these are SI prefixes, every factor is an exact power of ten, and each step of k or M multiplies by 1,000 while m and µ divide by 1,000.
The principle
The volt is the SI unit of electric potential difference: one volt is one joule of energy per coulomb of charge, or equivalently one watt per ampere (1 V = 1 J/C = 1 W/A). The unit itself never changes when you add a prefix; the prefix only scales the number, just as a kilometre is 1,000 metres. So converting voltage is simply moving the decimal point by three places for each prefix step. The calculator displays very small results in scientific notation, for example 1 × 10⁻⁹ for a millivolt expressed in megavolts.
Worked example
Default inputs: 1 millivolt to volts.
- 1 mV = 10⁻³ V.
- 1 × 0.001 ÷ 1 = 0.001 V.
- Other units: 1 mV = 1,000 µV, 0.000001 kV and 1 × 10⁻⁹ MV.
How to read the result
Some typical magnitudes: brain-wave (EEG) signals are in the tens of microvolts, heart (ECG) signals around a millivolt, a fresh AA alkaline cell about 1.5 V, mains electricity 220 V in Korea and 120 V in the United States, and transmission lines hundreds of kilovolts. If a converted result seems far outside the expected range for your situation, recheck the prefix you selected.
Common mistakes
- Confusing m (milli, 10⁻³) with M (mega, 10⁶); the case of the letter matters.
- Typing "u" or "mu" inconsistently for micro; the symbol is µ.
- Mixing voltage with power or energy; volts alone do not tell you watts unless current is known (P = V × I).
Frequently asked questions
How many millivolts are in a volt?
1,000 mV.
How do I convert kV to V?
Multiply by 1,000. 22.9 kV is 22,900 V.
Are these conversions exact?
Yes. SI prefixes are exact powers of ten, so there is no rounding apart from display.
Sources: BIPM, The International System of Units (SI Brochure), 9th edition, 2019 · NIST Special Publication 811 (2008), Guide for the Use of the SI