# How to Calculate Speaker Wattage

Image Credit: Speakers image by Haris Rauf from <a href='http://www.fotolia.com'>Fotolia.com</a>

When you're trying to match a sound system's output to speakers, you don't want to under-power the speakers, but you don't want to overpower them, either. A watt is the amount of work done by one volt moving one ampere (often called an "amp" of current) of electricity. A speaker's wattage is a description of its strength. Knowing the voltage of a power speaker and how many amps its circuitry is designed to carry, you can calculate the speaker's wattage using Ohm's Law, which describes the relationship between volts, amps and watts.

## Step 1

Read the printed information provided with the speaker. Determine what voltage the speaker requires for it to operate.

## Step 2

Investigate the speaker's amperage (the number of amps). It's either printed on a plate on the speaker or in the speaker's printed information.

## Step 3

Multiply the number of volts by the number of amps to determine how many watts the speaker uses. If the speaker operates at 110 VAC, at 2 amps, the speaker's wattage is 220 watts.

© 2020 Leaf Group Ltd. Leaf Group Media Manage Preferences