Tone Generator
Any frequency from 20 Hz to 20 kHz, four waveforms, note presets — generated live in your browser.
440 Hz
ReadyQuick frequencies
Note presets (A4 = 440 Hz, equal temperament)
Turn your system volume down first
Start at a low volume, especially with headphones and low bass tones, then raise it slowly.
Silence at 20 Hz or 20 kHz is normal (gear and hearing limits). For noise and sweeps, use the dedicated noise generator and frequency sweep pages.
This tool runs locally in your browser — no audio is uploaded.
How to use
- 1
Set the frequency
Drag the slider for a rough value or type an exact frequency. The readout shows the nearest musical note and how far off you are in cents.
- 2
Pick a waveform
Sine is pure and smooth; square, sawtooth, and triangle add harmonics and sound brighter or buzzier. Switching while playing is glitch-free.
- 3
Play and adjust
Press Play and adjust frequency or volume live. Keep the volume moderate — pure tones at high volume are tiring and can damage hearing over time.
How it works & limits
The tone is a single oscillator driven by the Web Audio API, computed sample-by-sample on your device. A4 = 440 Hz follows the modern concert pitch standard (ISO 16), and the note readout uses equal temperament with 12 semitones per octave, so you can dial in exact notes for tuning or experiments.
Very low and very high tones may be inaudible: 20 Hz is below what most speakers reproduce, and frequencies above roughly 15–17 kHz become harder to hear with age and equipment limits — silence at the extremes is normal, not a bug. Square and sawtooth waves carry strong harmonics that can sound harsh; start with sine. Long listening at high volume is not recommended for your ears or your speakers.
FAQ
Why can I not hear 20 Hz — or anything above 15 kHz?
Most speakers and headphones cannot reproduce 20 Hz as sound, and human hearing typically tops out between 15 kHz and 18 kHz, lower with age. The generator still produces the tone; your gear and ears set the limits.
Why does a square wave sound louder than a sine at the same volume?
A square wave contains many harmonics, so it carries more total energy at the same peak level. Drop the volume a few steps when switching from sine to square or sawtooth.
What are the note presets for?
They jump to common tuning notes: C4 (middle C), E4, G4, A4 (440 Hz concert pitch), and C5. Useful for tuning by ear, testing resonance, or quick instrument checks.
Can I generate white or pink noise here?
This page is tones only — the noise generator page handles white, pink, and brown noise with a sleep timer, and the frequency sweep page handles sweeps.
Is the frequency accurate?
Yes, within the precision of your device clock — typically a few cents at audio frequencies, far finer than the differences most people can hear.
Related tools
Frequency Sweep Test
Sweep 20 Hz–20 kHz with adjustable duration, direction, and linear/log scaling.
Open toolWhite & Pink Noise Generator
White, pink, and brown noise with a 15–120 minute timer for focus or sleep.
Open toolBass Test
Sine tones from 10–200 Hz with a descent mode to find your lowest audible/reproducible frequency.
Open toolHearing Range Test
Find the highest (and lowest) frequency you can hear — 20 Hz to 20 kHz, no diagnosis.
Open tool