Tone generator
Generate pure tones from 1 Hz to 22 kHz in sine, square, triangle or sawtooth waves – with octave jumps, fine tuning and frequency sweeps.
Decibel meter
Measure sound levels with your device's microphone: live dB reading, maximum and average (Leq), with a calibration offset.
Hearing test
Find the highest frequency you can hear with a quick headphone test – and see how it compares with typical hearing by age.
Spectrogram
See sound: a real-time spectrogram of your microphone or any audio file, with peak-frequency and note readout. Runs in your browser.
Wavelength calculator
Convert frequency to wavelength for sound in air (any temperature), water, steel, helium and 40+ materials.
Frequency to note
Convert any frequency to the nearest musical note with cents deviation, or a note to its frequency – with adjustable A4 reference pitch.
RT60 calculator
Estimate a room's reverberation time (RT60) from its size and surface materials with the Sabine and Eyring formulas.
Decibel calculator
Add or average several sound levels in dB, and convert a decibel difference into power, pressure and perceived loudness ratios.
Sound vs distance
Estimate how loud a sound will be at another distance using the inverse square law for point sources or the 3 dB rule for line sources.
Noise exposure calculator
How long can you safely listen at a given dB level? Calculate your daily noise dose against NIOSH and OSHA limits.
Speed of sound calculator
Calculate the speed of sound in air at any temperature in m/s, km/h, mph and ft/s.
BPM to ms
Convert tempo (BPM) into delay and reverb times in milliseconds for every note value – straight, dotted and triplet.
Audio file size
How much space will a recording take? Calculate WAV/PCM size from sample rate, bit depth and channels, and compressed size from bitrate.
Lightning distance
How far away is the storm? Count the seconds between lightning and thunder to get the distance in km and miles.