Inverse Square Law SPL Predictor

Enter an SPL reading you've measured (or a spec'd max output) at a known distance, then a second distance you want to predict for. This applies the inverse square law to estimate how much level you'll lose or gain moving further from or closer to the source — handy for checking whether the back of a room will get enough level, or whether front-of-stage will be uncomfortably loud, before you've walked the room with an SPL meter.

Known SPL (dB) at reference distance Reference distance (m) Target distance (m) Calculate