Voltage Converter: From Volts to Kilovolts, Millivolts & More

Converting between different voltage units, such as Volts (V), Millivolts (mV), and Kilovolts (kV), is essential for electronics projects, scientific measurements, and understanding electrical specifications. Our simple and accurate voltage converter provides instant conversions to help you with your calculations.

Instantly convert between different units of voltage.

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How to Use Our Voltage Converter

Using this tool is straightforward. It allows you to convert any voltage value from one unit to another seamlessly.

Enter Voltage Value: Type the numerical value of the voltage you want to convert into the input box.
Select Starting Unit: In the first dropdown menu, choose the unit you are converting from (e.g., Volts, Kilovolts).
Select Target Unit: In the second dropdown menu, choose the unit you want to convert to (e.g., Millivolts, Microvolts).

The calculator will instantly display the converted value. For example, to convert 120 Volts to Kilovolts, enter “120”, select “Volts (V)”, and select “Kilovolts (kV)”.

Input Fields Explained:

Voltage: The numerical amount of electric potential difference you are starting with.
From Unit: The unit of measurement for your initial voltage value.
To Unit: The unit of measurement you wish to see your final result in.

Understanding Your Results

The number our calculator provides is the equivalent electrical potential difference in the new unit you selected. Understanding the scale of these units is key to interpreting your results correctly.

What is Voltage? Think of voltage as electrical pressure. In a water pipe, pressure is what pushes the water through. In an electrical circuit, voltage is the force that pushes charged electrons (the current) through a wire. It’s measured in Volts (V). Larger voltages mean more “push,” while smaller voltages mean less.

Common Voltage Units and Scale

The units in our converter use standard SI (International System of Units) prefixes. Each prefix represents a power of 10 relative to the base unit, the Volt. This table breaks down the most common units.

Unit	Symbol	Relation to 1 Volt	Real-World Example
Gigavolt	GV	$1, 000, 000, 000$ Volts	A very large lightning bolt can have a potential of up to 1 GV.
Megavolt	MV	$1, 000, 000$ Volts	Major electrical power transmission lines can operate at over 1 MV.
Kilovolt	kV	$1, 000$ Volts	Neighborhood power distribution lines typically run at several kilovolts (e.g., 7.2 kV).
Volt	V	Base Unit	Standard household batteries (AA, AAA, C, D) are 1.5V. A car battery is 12V. Wall outlets in the US are 120V.
Millivolt	mV	$0.001$ Volts	The electrical signals in the human body, like those measured by an ECG (electrocardiogram) or EEG (electroencephalogram), are in the millivolt range.
Microvolt	µV	$0.000001$ Volts	Faint signals from radio antennas or sensitive biomedical sensors are often measured in microvolts.
Nanovolt	nV	$0.000000001$ Volts	Used in highly sensitive scientific research, such as measuring thermal noise or Johnson noise in resistors.

The conversion is a matter of moving the decimal point. For instance, to convert from Volts to Kilovolts, you divide by 1,000. To convert from Volts to Millivolts, you multiply by 1,000.

Frequently Asked Questions

What is the difference between Voltage, Current, and Resistance?

This is one of the most fundamental concepts in electronics, explained by Ohm’s Law. The easiest way to understand it is with the water pipe analogy:

Voltage (V) is like the water pressure. It’s the force pushing the water.
Current (I), measured in Amperes (Amps), is like the flow rate of the water. It’s the amount of electricity actually moving through the wire.
Resistance (R), measured in Ohms ( $O m e g a$ ), is like the width of the pipe. A narrow pipe has high resistance and restricts water flow, while a wide pipe has low resistance and allows more flow.

Ohm’s Law ties them together: Voltage = Current × Resistance ( $V = I R$ ). You need enough voltage (pressure) to overcome the resistance (pipe narrowness) to get a certain amount of current (flow).

Why do different countries use different voltages (120V vs. 240V)?

The difference is historical. In the late 19th century, Thomas Edison’s DC (Direct Current) system in the US was based around 110V. When AC (Alternating Current) became the standard, the infrastructure was already built, so 120V (at 60 Hz) became the American standard for convenience.

In Europe, companies like Germany’s AEG saw the benefits of a higher voltage. A higher voltage allows you to deliver the same amount of power with less current ( $P = V t im es I$ ). Less current means you can use thinner, cheaper copper wires without them overheating, making the grid more efficient over long distances. They chose 220V, which eventually became the 230V-240V (at 50 Hz) standard across much of the world.

Can I use my 120V appliance in a 240V country?

No, not directly! Plugging a device designed for 120V into a 240V outlet will send twice the electrical pressure it was designed for. This will overwhelm the circuitry, likely destroying your appliance instantly and creating a fire hazard.

To use a 120V appliance in a 240V country, you need a step-down voltage converter. This is a device that plugs into the 240V wall outlet and safely reduces the voltage to 120V for your appliance.

What is the difference between a travel adapter and a voltage converter?

This is a critical distinction for travelers:

A Travel Adapter is a small, simple device that only changes the plug shape. It allows your American-shaped plug to fit into a European, British, or Australian-shaped outlet. It does not change the voltage.
A Voltage Converter is a larger, heavier electrical device containing a transformer. Its job is to change the voltage level itself (e.g., from 240V down to 120V).

Many modern electronics like laptops and phone chargers are “dual voltage” (look for “INPUT: 100-240V” on the power brick). These devices only need a simple travel adapter. However, single-voltage items like hair dryers, curling irons, and electric razors need a proper voltage converter.

What is AC vs. DC voltage?

Direct Current (DC): The flow of electricity is constant and in one direction. Think of water flowing steadily through a hose. Batteries, solar cells, and the power adapters for your electronics provide DC voltage.
Alternating Current (AC): The flow of electricity rapidly changes direction, alternating back and forth. The power that comes from wall outlets is AC. In the US, it alternates 60 times per second (60 Hz); in most of the world, it’s 50 times per second (50 Hz). AC is used for power grids because it can be easily “stepped up” to high voltages for efficient long-distance transmission and “stepped down” for safer use in homes.

What are step-up and step-down converters?

These devices use transformers to change AC voltage levels without changing the power significantly.

Step-Down Converter: Decreases voltage. It has more wire turns in the primary coil (input) than in the secondary coil (output). This is what you’d use to run a 120V American appliance in a 240V European country.
Step-Up Converter: Increases voltage. It has fewer wire turns in the primary coil and more in the secondary. This is less common for consumers but is used, for example, to run a 240V European appliance in the 120V United States.

Is high voltage always dangerous?

Not necessarily on its own. Danger to the human body is primarily a function of current, not voltage. A shock of just 100 milliamps (0.1A) can be fatal.

However, voltage and current are linked by Ohm’s Law. High voltage has a greater ability to push a dangerous amount of current through the resistance of your body. A static shock from a doorknob can be thousands of volts, but the current is incredibly tiny and lasts for a microsecond, so it’s harmless. The 120V from a wall outlet, however, can push a lethal amount of current through you because the power source can supply it continuously.

What does “nominal voltage” mean?

“Nominal voltage” is the named or stated voltage of a system. For example, the US power grid is nominally 120V. In reality, the actual voltage delivered to your home can fluctuate. It might be 115V, 118V, or even 122V at any given moment depending on the load on the grid. This variation is normal and within acceptable limits for your appliances.

How do I measure voltage?

You measure voltage using a tool called a multimeter (or voltmeter). To measure the voltage of a battery, you would set the multimeter to “DC Voltage,” touch the red probe to the positive (+) terminal and the black probe to the negative (-) terminal. The screen will then display the voltage.

Why are power lines so high voltage?

Power is calculated as Power = Voltage × Current. Electrical energy is lost as heat in the transmission wires, and this heat loss is proportional to the square of the current ( $P_l oss = I^{2} R$ ).

By transmitting electricity at a very high voltage (e.g., 500 kV), power companies can send the same amount of power with a very low current. This drastically reduces the energy lost to heat over hundreds of miles of power lines, making the grid far more efficient. Substations then “step down” this high voltage to safer levels for use in neighborhoods and homes.

Now that you’ve converted your voltage values, you may want to calculate other electrical properties. Use our Ohm’s Law Calculator to find relationships between voltage, current, and resistance. Or, if you need to determine the energy consumption of an appliance, check out our Watts to Amps Calculator.

Creator

Tien Dung Nguyen

A results‑oriented backend and full‑stack software engineer with extensive experience in Go, Node.js and React, plus tools like Docker, PostgreSQL and RabbitMQ. He has progressed from junior to senior roles, spearheading scalable microservice architectures and mentoring teams while delivering end‑to‑end solutions that improve user experiences.

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