Enter your Speaker Impedance, Sensitivity, Listening Distance, and Desired Peak SPL into the Car Audio Amplifier Power Calculator to find your Required RMS Power, then fine-tune with Channels, Bridged Config, and Battery Voltage to get Current Draw and Total System Power.
Required RMS Power
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Current Draw
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Total Input Power
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Output Voltage (RMS)
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Recommended Fuse
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Check your speaker specifications or manual. Impedance is usually 2, 4, or 8 ohms. Sensitivity is measured in dB SPL @ 2.83V at 1 meter and typically ranges from 80-100 dB for car speakers.
RMS power is continuous power handling, while peak power is maximum instantaneous power. Always match amplifier RMS output to speaker RMS rating for proper performance and safety.
Bridging combines two channels into one higher-power channel. This doubles power but also doubles the impedance load. Only bridge if your speakers can handle the increased power and your amp supports bridging.
Wire gauge depends on current draw and wire length. Higher current and longer runs require thicker wire (lower AWG numbers). Use the current draw result to select appropriate power and ground wire sizes.
Higher efficiency means less wasted power as heat. A 75% efficient amp drawing 100W from your battery only delivers 75W to speakers. Class D amps are typically 85-90% efficient, while Class A/B amps are 60-75%.
Several factors increase power requirements: low speaker sensitivity, high desired volume levels, listening distance, and room acoustics. Higher SPL targets require exponentially more power.
Use a fuse rating 25-50% higher than your calculated current draw to prevent nuisance blowing during peaks, but not so high that it won't protect your amplifier. The calculator provides a recommended starting point.
Yes, the same principles apply to subwoofer amps. Input your subwoofer's impedance and sensitivity. Subwoofers typically have lower sensitivity (80-90 dB) and may require significantly more power than full-range speakers.