Difference between VA and Watts

Volt-Ampere and Watts are power measurement units. Volt-ampere is used to measure the total power that is being consumed by a device. Watts is used to power the device so it can perform its useful work.

The product of voltage and current in an AC (alternating current) circuit is known as a unit of apparent power, or VA. It shows the overall power used by a device, which includes both the useful power used and the power lost as a result of inefficiencies like reactive power.

The real power used by a gadget to carry out productive work is measured in watts, which is a unit of real power. Watts is used to calculate electricity bills and to determine how much power various gadgets and appliances use.

Read this article to find out more about VA and Watts and how they are different from each other.

What is Volt-Ampere?

An electrical circuit's perceived power is measured in volt-amperes (VA). It is a result of an AC circuit's voltage (in volts) and current (in amperes).

Depending on the location, the frequency at which the current changes direction in an AC circuit is typically between 50 and 60 hertz (Hz). As a result, the actual power and the reactive power are the two parts of the power in an AC circuit. Reactive power, measured in VAR (Volt-Ampere Reactive), is the power used by inductors and capacitors to store and release energy during the AC cycle. Real power, measured in Watts, is the real power used by a device to accomplish practical work.

The apparent power, which is expressed in VA and represents the overall power in an AC circuit. The total amount of power that the circuit draws from the source is represented by apparent power, which is the vector sum of real and reactive power. The power triangle explains how real, reactive, and seeming power relate to one another.

The size of the power system required to operate a device is dependent on the device's VA rating. A device needs a power system that can provide at least 1000 volts of visible power to function, for instance, if it has a VA rating of 1000 volts. To make sure that linked devices can receive enough power from power systems, such as UPS (uninterruptible power supplies), this is crucial when planning and sizing them.

VA is a measure of apparent power, which is different from real power; it is crucial to mention. The power factor, which measures how effectively a device uses the available power to produce useful work, is generally defined as the ratio of real power (measured in watts) to perceived power (measured in VA). Lower power factors signify device inefficiencies, while a power factor of 1 implies complete efficiency. For planning and running electrical systems effectively, it is crucial to comprehend the link between real power, reactive power, and visible power.

What is Watts?

In an electrical circuit, real power is measured in watts. It is a measurement of the actual power that a device actually uses to carry out a valuable job. By multiplying the voltage (in volts) by the current (in amperes) and then by the power factor—a measurement of how effectively the device transforms available power into productive work—watts are created.

Both AC and DC circuits can have their power consumption measured in watts. Since the voltage and current in DC circuits are both constant, calculating the real power is simple. The phase angle between the voltage and the current must be taken into consideration when calculating real power in AC circuits because the voltage and the current alternate directions occasionally.

The efficiency of a device in transforming available power into useful work is indicated by its power factor. It measures how much of the total power consumed is really put to use by comparing real power (measured in watts) to apparent power (measured in VA). Inefficiencies in the device, such as reactive power, are indicated by a power factor of less than 1, while a power factor of 1 shows perfect efficiency.

Difference between VA and Watts

The following table highlights the major differences between VA and Watts −





Volt-Ampere (VA) is an abbreviation for Volt-Ampere.

Watts is the abbreviation for Watts.


Power factor = real power (watts)/apparent power (VA)

Power factor = read power (watts) / (voltage × current)


VA or kVA (kilovolt-ampere)

W (watts) or kW (kilowatts)


The volt-ampere was once used to represent apparent power.

Watts is used to represent real power.


Volt-Ampere is a unit of measurement for ammeters and voltmeters.

Watts is used to measure voltmeters and ammeters.


Volt-Ampere devices include bulbs, motors, and transformers.

Some of the examples of devices that use wattage are electronic devices, light bulbs, and heaters.

Direct Current

Direct current is not applicable for the volt-ampere

Watts is applicable to direct current.

Alternate Current

The Volt-Ampere is applicable to alternate current.

For less than watts, alternate current is appropriate.


In conclusion, Watts and VA are power measurement units. Volt-ampere is used to measure the total power that is being consumed by a device. Watts is used to power the device so it can perform its useful work.

Although Watts is used to rate the power consumption of devices and appliances, VA is used to size power systems, such as uninterruptible power supplies (UPS), to ensure they can provide enough power to connected devices. For the efficient design, sizing, and operation of electrical systems and devices, it is crucial to understand the distinctions between VA and Watts.