This tool finds the** current consumption of a speaker** (in Amperes or simply Amps). This is used to determine the cable thickness and specifications for the relay.

Enter

- Power rating of the amplifier driving the speaker (P)
- Speaker Impedance (R)

**Formula**

**I = √ (P/R)**

**Example Calculation**

Consider an amplifier that’s rated for **50 Watt** RMS (Root-mean-square) driving a speaker with an impedance of **8 ohm**. In this case the current drawn by the speaker will be **2.5 Amps**.

Note that while the amplifier might be rated for a certain power level, it is not always delivering this much power. As a result the current consumption will typically be lower than the max number that this calculator provides.

**Related Calculators**

- Speaker Impedance – calculate the impedance of speakers in either parallel or series configuration