Convert Apparent Power from Volt-Amperes to Millivolt-Amperes (VA to mVA)

Volt-Ampere to Millivolt-Ampere Conversion Formula

To convert apparent power from volt-amperes (VA) to millivolt-amperes (mVA), multiply by 1,000.

• mVA = VA × 1,000

The milli prefix means one thousandth, so one volt-ampere contains exactly 1,000 millivolt-amperes. Divide by 1,000 to go from mVA back to VA.

Step-by-Step Example

A plug-in energy monitor reports that a television in standby draws 0.45 VA of apparent power. A datasheet comparison table is kept in mVA:

1. Take the apparent power: 0.45 VA
2. Multiply by 1,000: 0.45 × 1,000 = 450 mVA

Stated as 450 mVA, the figure lines up directly against a competing model's quoted 300 mVA standby draw.

Quick Reference Table

The Scale of Standby and Signal Power

Millivolt-amperes appear where AC power is almost, but not quite, zero. Standby electronics are the most common case: modern efficiency rules push no-load losses of chargers and appliances below 0.5 W, and at those levels the apparent power — often several times the real power, because tiny switched-mode supplies present a poor power factor — is naturally quoted in hundreds of mVA. Instrumentation is the other habitat: the excitation of a small sensor, the burden a measuring relay places on an instrument transformer's secondary, or the AC drive level of an impedance bridge may each amount to only a few mVA. The conversion itself is a clean ×1,000, but two habits keep the numbers meaningful. First, remember that VA ≥ W always — if a device claims 200 mW standby real power, its mVA figure can legitimately be 400–600 mVA without anything being wrong. Second, watch the capital letters: mVA is millivolt-amperes, while MVA — the same letters with a capital M — is a billion times larger. Context usually disambiguates, but on a keyboard the two are one shift-key apart.

How many volt-amperes are in one millivolt-ampere? One Millivolt-Ampere (mVA) contains 0.001 Volt-Amperes (VA) — the inverse of the factor above. Multiplying by 1000 takes you from volt-amperes to millivolt-amperes; multiplying by 0.001 brings you back.

Put in words: one volt-ampere equals 1000 millivolt-amperes, so the volt-ampere is the larger unit of this pair. Converting between them never changes the amount of apparent power being measured — only the size of the unit you count it in.

What is a Volt-Ampere (VA)?

A Volt-Ampere (VA) is a unit of measurement for "apparent power" in an electrical circuit.

It represents the total power supplied by a source, which is critical for understanding a device's full electrical load.

Understanding Apparent Power vs. Real Power

Think of VA as the total potential power a device can draw.

In contrast, Watts (W) measures the actual working power the device consumes.

This is the key difference between "apparent power" (VA) and "real power" (Watts). The VA rating is always greater than or equal to the wattage.

The difference between these two measurements is known as the "power factor (PF)."

Why VA is Used for Sizing Equipment

The VA rating is crucial for correctly sizing equipment like uninterruptible power supplies (UPS) and transformers.

Why? Because these devices must support the entire electrical load—which includes both real and reactive power—not just the power being actively used.

Sizing a UPS based only on Watts could lead to overloading and system failure, as it wouldn't account for the total current the connected devices draw.

The Simple Calculation for Volt-Amperes

The formula to calculate Volt-Amperes is straightforward:

VA = Volts × Amperes

By multiplying a device's operating voltage by the current (in amps) it draws, you can determine its apparent power.

This calculation is essential for IT professionals and electricians when assessing power needs or planning for new hardware.

What is a Millivolt-Ampere (mVA)?

A Millivolt-Ampere (mVA) is a unit of measurement for apparent power, formally recognized by the International System of Units (SI).

It is a tiny unit, equal to exactly one-thousandth of a Volt-Ampere (0.001 VA).

Because this unit is so small, it is not used for common household appliances but is instead used to measure the power in low-energy systems.

You will typically find mVA used in specifications for:

• sensitive electronics
• small transformers
• medical devices
• precision sensors

What Does mVA Measure? (Apparent Power vs. True Power)

The Millivolt-Ampere (mVA) is a unit of apparent power. This is the total power in an AC (alternating current) circuit.

However, it's not the same as the "true power" (measured in Watts) that actually does work, like lighting a bulb.

A simple way to understand this is the "beer analogy":

• True Power (Watts): This is the beer itself—the part you actually want that does the "work."
• Reactive Power (VAR): This is the foam on top. It's not beer, but it's still part of what's in the glass and takes up space.
• Apparent Power (VA or mVA): This is the total of the beer and the foam. It represents the full load the circuit must be able to handle.

Engineers use mVA to precisely measure this total load in very sensitive, low-power circuits.

How to Convert Millivolt-Amperes (mVA) to Volt-Amperes (VA)

The conversion between mVA and its base unit, the Volt-Ampere (VA), is very straightforward. The prefix "milli" means "one-thousandth."

• 1 mVA = 0.001 VA
• 1,000 mVA = 1 VA

This simple 1,000-to-1 ratio makes it easy to scale measurements.

For example, a small electronic component rated at 250 mVA is drawing 0.25 VA of apparent power.

Volt-Ampere to Millivolt-Ampere Conversion Table

Here are some quick reference conversions from Volt-Ampere (VA) to Millivolt-Ampere (mVA):

This conversion in other languages

Engineering datasheets across Europe write Volt-Ampere to Millivolt-Ampere several different ways. The calculation is the same in every one of them.