Voltage Converter

Convert between volts, millivolts, kilovolts, and microvolts — for electronics, electrical systems, and power transmission.

Voltage

V, mV, kV

From

Result

1000

1 V = 1000 mV

Popular conversions

What Is a Voltage Converter?

A voltage converter (in the unit sense) translates electric potential between prefixes — volts to millivolts, kilovolts to volts, microvolts to millivolts. Voltage is the electrical 'pressure' that pushes current through a circuit, and the SI unit is the volt (V): one joule of energy per coulomb of charge. From the microvolts of a sensor signal to the kilovolts of a transmission line, voltage spans a wide range handled by metric prefixes.

This converter routes through the volt using exact power-of-ten prefixes. Note this is unit conversion, not a physical voltage transformer — it changes how a potential is expressed, not the voltage itself. Enter a value in any prefix and read it across microvolts, millivolts, volts, and kilovolts at once.

This is one category of the full Unit Converter — pair it with our percentage calculator or scientific calculator for related everyday maths.

How Voltage Conversion Works

Everything routes through the volt

Each prefix has a fixed power-of-ten link to the volt. The converter normalises to volts, then projects to every other prefix.

Metric prefixes scale by 1,000

1 V = 1,000 mV = 1,000,000 µV; 1 kV = 1,000 V. Each step shifts the decimal point three places.

Voltage is energy per charge

1 V = 1 joule/coulomb. It's the potential difference that drives current — the 'push' in Ohm's law, V = I × R.

Unit change, not transformation

This converts how voltage is written (V to mV, etc.); it doesn't step voltage up or down like a physical transformer.

Core Voltage Conversion Factors

Each step is a power of ten. Multiply to reach volts; divide to come back.

V → mV

× 1000

One volt is 1,000 millivolts. Sensor and audio signals often live in millivolts.

kV → V

× 1000

One kilovolt is 1,000 volts, used for transmission and high-voltage equipment.

Ohm's law

V = I × R

Voltage equals current times resistance — the link to current and resistance conversions.

How to Use the Voltage Converter

1
Enter the voltage value
Type the voltage you want to convert — a battery rating, a signal level, a line voltage.
2
Choose the 'from' unit
Pick volts, millivolts, microvolts, or kilovolts as your starting prefix.
3
Choose the 'to' unit
Select the target prefix, or swap the two to reverse direction.
4
Read every prefix at once
The all-units table shows the voltage across µV, mV, V, and kV together.

Key Voltage Concepts

Volt

The SI unit of electric potential: one joule per coulomb. A potential difference of one volt across one ohm drives one ampere of current.

Millivolt and microvolt

1 mV = 0.001 V; 1 µV = 0.000001 V. Sensor outputs, thermocouples, and biological signals (ECG) are measured here.

Kilovolt

1,000 volts. Power transmission lines run at tens to hundreds of kilovolts to reduce current and transmission losses.

Voltage in Ohm's law

Voltage is current times resistance (V = IR). It's the driving potential; pair voltage with current and resistance to analyse circuits.

Real-World Voltage Conversions

🔋

Batteries

A 1.5 V AA cell is 1,500 mV; a 3.7 V lithium cell is 3,700 mV. Battery and electronics specs flip between V and mV.

🏠

Mains voltage

Mains is 120 V (US) or 230 V (Europe). Appliances and outlets are rated in volts.

🎤

Audio signals

A microphone outputs a few millivolts; line level is about 1 V. Audio engineering works across mV and V.

⚡

Power transmission

High-voltage lines run at 110 kV to 765 kV (110,000–765,000 V). Kilovolts dominate the grid.

🩺

Biomedical signals

An ECG signal is about 1 mV; brain (EEG) signals are microvolts. Medical instrumentation measures tiny voltages.

📟

Logic levels

Digital logic uses 3.3 V or 5 V (3,300 or 5,000 mV). Microcontroller and sensor circuits convert between these.

Best Practices for Voltage Conversion

✓Carry the prefix precisely. mV and V differ by 1,000; kV and V by 1,000. A dropped prefix mis-sizes a signal or a line voltage by orders of magnitude.
✓Distinguish unit conversion from transformation. Converting V to mV changes notation, not the actual voltage. Stepping voltage up/down requires a physical transformer, not arithmetic.
✓Use Ohm's law to sanity-check. V = I × R relates voltage to current and resistance. Cross-check a converted voltage against the circuit's other quantities.
✓Mind RMS vs peak for AC. AC voltage can be quoted as RMS or peak (peak ≈ 1.414 × RMS). The prefix conversion doesn't address which is meant.
✓Respect high-voltage safety. Kilovolt-scale potentials are lethal. Voltage conversions in high-voltage contexts demand appropriate caution and qualified handling.

Common Voltage Conversion Mistakes

Dropping a metric prefix

Reading mV as V, or kV as V, shifts the voltage 1,000-fold — a serious error for both signals and power systems.

Confusing unit change with transformation

Converting 230 V to 230,000 mV is just notation. It doesn't 'transform' the voltage; that needs physical equipment.

Mixing RMS and peak AC voltage

AC figures may be RMS or peak. Comparing one to the other without the 1.414 factor misjudges the actual voltage.

Treating voltage as power

Volts aren't watts. Power is voltage × current, so a voltage value alone doesn't tell you the power involved.

Why Voltage Conversion Matters

Voltage spans the microvolts of a brainwave to the kilovolts of a transmission line, and getting its prefix right is essential for instrumentation, electronics, and power systems alike. A dropped prefix can mismatch a logic level, misread a biomedical signal, or dangerously misjudge a line voltage — none of which tolerate a factor-of-1,000 slip.

Because voltage drives current through Ohm's law and combines with it to give power, accurate voltage units keep circuit analysis and energy calculations coherent. A converter that routes through the volt and surfaces µV, mV, V, and kV together lets engineers, technicians, and students work at the right scale across the whole electrical landscape.

Built for electronics and power engineers, electricians, biomedical technicians, and students converting between volts, millivolts, and kilovolts.

Linear unit factors follow the BIPM SI brochure, the NIST Guide to the SI, and ISO 80000. Currency rates load live from open.er-api.com; crypto prices from CoinGecko. See our methodology and editorial policy. Educational only — not certified for regulated trading, settlement, medical, or aerospace use.

Voltage Converter FAQs

Multiply volts by 1,000 to get millivolts, since one volt is 1,000 mV. So a 1.5 V battery is 1,500 mV, and a 1 mV sensor signal is 0.001 V. To convert to microvolts, multiply by 1,000 again (1 mV = 1,000 µV).

The volt is the SI unit of electric potential difference, equal to one joule of energy per coulomb of charge. A potential of one volt will drive a current of one ampere through a resistance of one ohm, per Ohm's law (V = I × R).

No. This tool converts how a voltage is expressed between units (volts, millivolts, kilovolts) — it's arithmetic, not electrical. Physically stepping a voltage up or down (like a mains adapter or grid transformer) requires actual transformer hardware, not a unit conversion.

One kilovolt is 1,000 volts, and one megavolt is 1,000 kV (a million volts). Power transmission lines operate at tens to hundreds of kilovolts — for example, 110 kV is 110,000 V — to reduce current and minimise transmission losses.

For alternating current, RMS (root-mean-square) voltage is the effective value used for power calculations, while peak voltage is the maximum instantaneous value. Peak is about 1.414 times the RMS for a sine wave, so 230 V RMS mains peaks at about 325 V. A unit converter handles prefixes, not the RMS/peak distinction.

It uses exact metric-prefix definitions (1 V = 1,000 mV = 10⁶ µV, 1 kV = 1,000 V) and routes every conversion through the volt at full precision, so the result is exact to your input precision.