Tone & Frequency Generator

This tool plays a pure, precisely pitched tone from 20 Hz to 20 kHz — the span of human hearing — synthesised live by your browser's audio engine. The slider moves logarithmically, like hearing does, so the musically useful range doesn't crowd into the first centimetre. Type an exact frequency, or use the presets.

Tuning an instrument

The 440 Hz preset is A4 concert pitch, the standard reference for tuning. Play it, match your instrument's A, and tune the rest relative to it. The read-out shows the nearest note name for whatever frequency you dial in, so you can generate any reference pitch (e.g. 82.4 Hz for a guitar's low E).

Testing speakers and headphones

Use the Left only / Right only channel switch to confirm your speakers are wired the right way round and both drivers work — the classic stereo test. Sweep the low presets to find where your speakers give up: many small speakers produce little below 100 Hz, and a rattle or buzz on a pure low tone points to a loose driver or resonating furniture. The 1 kHz tone is the standard reference level engineers use to calibrate equipment.

The hearing-range check (with a caveat)

Human hearing tops out around 20 kHz in childhood and drifts down with age; many adults hear little above 15–16 kHz. Trying the high presets is a fun, rough self-check — but this is not a hearing test: your speakers, volume setting, and room matter as much as your ears. If you have real concerns about your hearing, see an audiologist for a calibrated audiogram.

Privacy & safety

The tone is generated on your device by the Web Audio API — nothing is downloaded, uploaded, or logged. Volume defaults low on purpose: pure tones concentrate all their energy at one frequency, so treat loud high-pitched tones with the same respect as any loud sound, especially in headphones.