To convert volts to millivolts, multiply by 1000. That factor is the whole relationship: both units measure the electrical potential difference driving a current, so the conversion is a proportion with no offset and no substance-specific constant.
The volt is the SI unit of electric potential: one joule of energy per coulomb of charge moved. Millivolts are the working scale of sensors and thermocouples, where the whole usable signal may span less than a volt.
Below the calculator there is a step table for the values people look up most, and a second table putting real the electrical potential difference driving a current figures into millivolts so the number you get has something to be compared against.
The formula
volts- The amount you are converting, in volts
1000- The exact number of millivolts in one volt
millivolts- The converted result
How it works, step by step
- Enter the value in volts.
- It is multiplied by 1000, the exact factor between the two units.
- The answer is shown in millivolts, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Overhead distribution line: 1.1e+04 V in millivolts
At 1.1e+04 V (overhead distribution line), the same quantity in millivolts is 1.1e+04 × 1000 = 1.1e+07 mV. One volt is 1000 millivolts, so the numbers grow as expected.
USB bus: 5 V in millivolts
Take usb bus, roughly 5 V. The conversion is a single multiplication — 5 × 1000 — giving 5000 mV. Because the relationship is proportional, doubling the input doubles the answer to 10,000 mV.
How to read your score
Frequently asked questions
How many millivolts are in one volt?
Exactly 1000. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert volts to millivolts?
millivolts = volts × 1000. Reversed, volts = millivolts ÷ 1000, which is the same as multiplying by 0.001.
Which is the bigger unit, the volt or the millivolt?
The volt. One volt equals 1000 millivolts.
What does this quantity actually measure?
Both units measure the electrical potential difference driving a current. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a volt?
The volt is the SI unit of electric potential: one joule of energy per coulomb of charge moved.
What is a millivolt?
Millivolts are the working scale of sensors and thermocouples, where the whole usable signal may span less than a volt.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Volts to millivolts reference tables
| Volts | Millivolts |
|---|---|
| 0.5 V | 500 mV |
| 1 V | 1000 mV |
| 2 V | 2000 mV |
| 3 V | 3000 mV |
| 5 V | 5000 mV |
| 10 V | 10,000 mV |
| 20 V | 20,000 mV |
| 25 V | 25,000 mV |
| 50 V | 50,000 mV |
| 75 V | 75,000 mV |
| 100 V | 100,000 mV |
| 250 V | 250,000 mV |
| 500 V | 500,000 mV |
| 1000 V | 1e+06 mV |
| 5000 V | 5e+06 mV |
Exact factor: 1 volt = 1000 millivolts.
| Quantity | V | mV |
|---|---|---|
| AA alkaline cell | 1.5 V | 1500 mV |
| USB bus | 5 V | 5000 mV |
| Car battery | 12.6 V | 1.26e+04 mV |
| UK mains | 230 V | 2.3e+05 mV |
| US mains | 120 V | 1.2e+05 mV |
| Overhead distribution line | 1.1e+04 V | 1.1e+07 mV |
Published reference values, converted with the same factor this page uses.