Church PA System Sizing Calculator
Estimate the acoustic output and power needed to cover your sanctuary. Unlike the old “watts per person” rule, this calculator uses speaker sensitivity, listening distance, target sound pressure level, and peak headroom.
Sanctuary & Loudspeaker Information
Estimated Results
This is an estimated combined peak electrical power for the number of speakers entered, based on your room information. It is a starting point for choosing equipment—not an exact speaker wattage rating or amplifier recommendation. Actual requirements depend on speaker efficiency, coverage and room acoustics.
Room dimensions and mounting height estimate the direct path to a rear-center listener. The calculation assumes a single point-source loudspeaker in free-field conditions. It does not add output from multiple speakers at the listener, so multiplying by speaker count is only an illustrative equipment total.
How the Calculation Works
Required watts = 10^((target SPL − sensitivity + 20 × log₁₀(distance in meters)) / 10)
Peak watts = required watts × 10^(headroom dB / 10)
This is an educational preliminary estimate, not a final loudspeaker or amplifier recommendation. Real rooms have reflections, absorption, varying coverage and reverberation. Actual loudspeakers exhibit power compression and frequency-dependent performance. Powered line arrays should be assessed using their manufacturer's maximum SPL, coverage data, DSP and acoustic prediction tools. Never assume the calculated peak wattage is an appropriate amplifier rating or safe continuous power for a particular cabinet.
For church sound, prioritize speech intelligibility, consistent coverage, comfortable listening levels and sufficient headroom—not simply maximum wattage.