Voltage Converter - Convert Between Volts, Millivolts, Kilovolts Online Free

What Is a Voltage Converter?

A voltage converter is a tool that converts electrical voltage measurements between different units: Volts (V), Millivolts (mV), Kilovolts (kV), and Microvolts (uV). Whether you are an electrical engineer designing circuits, a student learning about electricity, or a hobbyist working on an electronics project, this tool provides instant and accurate voltage conversions.

In addition to unit conversion, this tool includes a voltage divider calculator that computes the output voltage from an input voltage and two resistor values, a fundamental circuit used throughout electronics for signal conditioning and reference voltage generation.

Voltage Units Explained

Voltage is the electrical potential difference between two points in a circuit, measured in Volts (V). Depending on the application, voltage may be expressed in different units:

• Volts (V) — The standard unit of voltage in the International System of Units (SI). Used for most everyday and industrial voltage measurements.
• Millivolts (mV) — One thousandth of a volt (1 mV = 0.001 V). Common in sensor outputs, audio signals, and low-power electronics.
• Kilovolts (kV) — One thousand volts (1 kV = 1,000 V). Used for high-voltage applications such as power transmission, X-ray equipment, and lightning measurements.
• Microvolts (uV) — One millionth of a volt (1 uV = 0.000001 V). Found in sensitive instrumentation, biomedical signals (ECG, EEG), and RF circuits.

How to Use the Unit Converter

1. Enter the voltage value — Type the number into the input field.
2. Select the input unit — Choose the unit of the value you entered (V, mV, kV, or uV).
3. Select the output unit — Choose the unit you want to convert to.
4. View the result — The converted value appears instantly.

Conversion Formulas

Converting between voltage units is straightforward using these relationships:

• V to mV: Multiply by 1,000 (e.g., 5 V = 5,000 mV)
• V to kV: Divide by 1,000 (e.g., 5,000 V = 5 kV)
• V to uV: Multiply by 1,000,000 (e.g., 0.003 V = 3,000 uV)
• mV to V: Divide by 1,000 (e.g., 250 mV = 0.25 V)
• kV to V: Multiply by 1,000 (e.g., 11 kV = 11,000 V)
• uV to V: Divide by 1,000,000 (e.g., 500,000 uV = 0.5 V)

Voltage Divider Calculator

A voltage divider is one of the most fundamental circuits in electronics. It consists of two resistors (R1 and R2) connected in series between an input voltage and ground. The output voltage is taken from the junction between the two resistors.

The voltage divider formula is:

Vout = Vin × R2 / (R1 + R2)

Where:

• Vin is the input voltage
• R1 is the resistance between the input and the output
• R2 is the resistance between the output and ground
• Vout is the output voltage at the junction

For example, with Vin = 12V, R1 = 10kΩ, and R2 = 20kΩ: Vout = 12 × 20,000 / (10,000 + 20,000) = 8V.

Important Limitations of Voltage Dividers

While voltage dividers are useful for signal-level applications, they have important limitations to keep in mind:

• Loading effect — Connecting a load to the output changes the effective resistance of R2, causing the output voltage to drop below the calculated value.
• Not a power supply — Voltage dividers waste power through the resistors and cannot supply significant current. Use a voltage regulator for power applications.
• No regulation — The output voltage varies proportionally with the input voltage. If the input fluctuates, the output fluctuates as well.

Peak vs. RMS Voltage

When working with AC (alternating current) voltages, it is important to distinguish between peak and RMS values:

• Peak voltage — The maximum value reached by the AC waveform from zero.
• RMS voltage — The effective DC-equivalent voltage. Most AC voltage ratings (e.g., 120V household outlets in the U.S.) are expressed in RMS.

For a sinusoidal waveform: Peak = RMS × √2 ≈ RMS × 1.414. Conversely, RMS = Peak / 1.414.

Common Voltage Levels

Here are some common voltage levels you may encounter:

• 1.8V to 3.3V — Logic levels in modern digital electronics and microcontrollers
• 5V — Standard USB voltage and common logic level for Arduino and older digital systems
• 12V — Automotive electrical systems and PC power supplies
• 24V — Industrial control systems and PLC I/O
• 120V / 230V — Household AC power (varies by country)
• 11kV to 33kV — Medium-voltage power distribution
• 110kV to 765kV — High-voltage transmission lines

Use Cases

Electronics Design

Design voltage divider circuits for sensor interfaces, ADC reference voltages, and signal conditioning. Calculate the exact resistor values needed to produce a specific output voltage from a given input.

Electrical Engineering

Convert between voltage units when working with specifications, component datasheets, or measurement equipment that uses different scales. Essential for power systems, instrumentation, and control engineering.

Education

Students learning Ohm\'s law, circuit analysis, and basic electronics can use this tool to verify their manual calculations and understand the relationship between voltage, current, and resistance.

Electronics Hobbyists

Whether you are building an Arduino project, working with sensors, or experimenting with circuits, converting between voltage units and calculating divider outputs is a daily task.

Related Tools

• Unit Converter — Convert between various measurement units including length, weight, temperature, and more.

Privacy

All calculations are performed entirely in your browser. No values or results are sent to our servers. We do not store, log, or share any information you enter. The tool works offline once the page has loaded.