Online decibel meter — free, no install
Measure ambient sound from your browser. Useful before you buy a generator, install an HVAC unit, or check whether the neighbour really is too loud at 11 pm. Audio is processed locally — nothing is recorded or uploaded.
We sample the microphone with the Web Audio API, compute RMS over a ~46 ms window, and convert to a dB SPL approximation. The calibration slider lets you align the reading with a known reference (a calibrated SLM, or a phone app that has been calibrated).
Phone and laptop mics have built-in AGC and a frequency response biased toward speech. They under-read low frequencies (HVAC rumble, generator chug) and clip above ~95 dB. Treat the result as a relative measurement.
Comparing two appliances side-by-side. Checking whether your standby generator install meets local noise ordinances. Verifying that an inverter is in its quoted dB range under load. For legal noise complaints you need a calibrated Class 1 meter.
Why we built this
Most "quiet" generator marketing is meaningless without a reference distance and a load. A 22 kW standby unit might be rated at 65 dB(A) at 7 m, half-load — that's the kind of small print that decides whether your neighbours will tolerate the install. This meter helps you do a sanity check on the unit you're considering, in the actual spot you'd put it.
Pair this tool with our sizing calculator and the LFP vs NMC chemistry guide before you commit to a backup power solution.