Volts to Millivolts Calculator

Direct answer

Multiply the entered volts value by 1000 to express it in millivolts (mV). This converts volt (V) to millivolt (mV) within the documented voltage family.

Variables and formula

• Volts (V): the source value measured in volt.
• Millivolts (mV): the same quantity expressed in millivolt.
• Conversion factor: 1000 millivolts per volt.

Millivolts = Volts × 1000

The generator emits numeric factors with at most 15 significant digits. Calculator results keep up to 10 significant digits for display; this formatting does not increase the precision of the measurement.

Unit definitions and named variants

Source unit: volt (V). The volt is the coherent SI derived unit of electric potential difference: 1 V = 1 W/A. The canonical volt definition is used; no alternate named variant is implied. Reference: Bureau International des Poids et Mesures: The International System of Units (SI), 9th edition, version 4.01.

Target unit: millivolt (mV). A millivolt is the SI decimal submultiple formed by applying milli (10^-3) to volt: 1 mV = 0.001 V. The canonical millivolt definition is used; no alternate named variant is implied. Reference: Bureau International des Poids et Mesures: The International System of Units (SI), 9th edition, version 4.01.

The V-to-mV direction remains inside the voltage quantity; it changes the unit label and numerical scale, not the kind of quantity being measured.

Relationship and precision

The named unit relationships are defined or exact, so the conversion is exact before display rounding and source-measurement uncertainty.

• V relationship: The base factor is exactly 1 by the family base-unit choice.
• mV relationship: The decimal-prefix relationship is exact.

To audit the factor through the family base unit, divide the raw dataset factors 1 by 0.001. The generator emits that quotient once at 15 significant digits as the canonical direct factor 1000; runtime calculations do not divide the already-emitted base factors again.

Reproducible example

For 10 volts, 10 × 1000 = 10000 millivolts. Repeating the same multiplication with the stated factor reproduces the displayed conversion before interface rounding.

Directional scale check

Because one volt contains 1000 millivolts, the target number is larger than the source number for every positive input. Zero maps to zero, while negative inputs are preserved as signed values under the stated direction convention.

Interpretation

Read the result as millivolts, not volts. A value entered as V leaves the calculator labelled mV; this directional distinction matters even when the two units describe the same voltage quantity.

Assumptions and limitations

• A negative value denotes polarity opposite the chosen positive reference.
• A conversion does not add significant figures to the source measurement.
• Signed values preserve reference polarity: a negative voltage means the measured polarity is opposite the chosen positive reference.

Common mistakes

• Voltage type such as RMS or peak must be stated separately.
• mV means millivolt; MV means megavolt.

Continue within the Voltage family

See the Voltage conversion hub for its five-unit reference table and all 20 directed routes.

• Reverse the direction: Millivolts to Volts
• Compare another voltage route: Volts to Microvolts
• Compare another voltage route: Volts to Kilovolts
• Compare another voltage route: Volts to Megavolts
• Compare another voltage route: Millivolts to Microvolts

Assumptions

• The entered value uses volts exactly as labelled.
• A negative value denotes polarity opposite the chosen positive reference.
• Rounding and measurement uncertainty remain the user's responsibility.

Sources and methodology

CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.

• The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; accessed Aug 7, 2026