Real oscillator audio
Powered by the Web Audio API's OscillatorNode, not a pre-recorded sample.
Tone Generator
Play a pure sine, square, sawtooth or triangle tone at any frequency and volume. A real oscillator, synthesized instantly in your browser.
440 Hz
Instant & click-free
Frequency and volume update live while the tone plays, with smooth ramping to avoid clicks.
Private by design
Everything runs locally in your browser. Nothing is recorded, uploaded, or saved.
How to use the tone generator
This free online tone generator synthesizes a pure test tone in real time using the Web Audio API. Pick a waveform, set a frequency, and press play to hear it instantly.
- Choose a waveformSelect sine, square, sawtooth or triangle depending on the tone character you need.
- Set the frequencyDrag the slider or type an exact value in Hz between 20 and 20,000.
- Play and adjustPress play, then fine-tune frequency and volume live while the tone sounds.
How the tone is generated
An OscillatorNode produces a continuous audio-rate waveform at whatever frequency you set, connected through a GainNode that controls volume and fades the signal in and out to avoid clicks and pops at the start and end.
Frequency range
The slider and numeric input cover 20Hz to 20,000Hz, matching the approximate range of human hearing from the lowest rumble to the highest audible pitch.
Waveform shapes
A sine wave contains only the fundamental frequency. Square, sawtooth and triangle waves add odd or even harmonic overtones on top of that same fundamental, changing the timbre without changing the pitch.
Live parameter changes
Moving the frequency or volume controls while the tone is playing updates the oscillator and gain nodes on the fly, so you hear the change immediately without restarting playback.
Common use cases
Test tones like this are used for speaker and headphone checks, hearing range tests, calibrating meters, tuning by ear, and as a raw source for sound design.
Tone generator FAQ
Quick answers about waveforms, frequency range, and audio privacy.
What is a tone generator used for?
It's used for testing speakers and headphones, tuning instruments, checking your hearing range, calibrating audio equipment, and general sound design experiments.
What frequency range can I generate?
You can generate any frequency between 20Hz and 20,000Hz, which is roughly the full range of human hearing.
What's the difference between the waveforms?
A sine wave is a pure single-frequency tone. Square, sawtooth and triangle waves contain the same fundamental frequency plus additional harmonic overtones, which is why they sound brighter or buzzier.
Will this damage my speakers or hearing?
High volumes at any frequency can be uncomfortable or damaging. Start at a low volume, especially at very high or very low frequencies, and reduce volume before switching waveforms.
Is any audio uploaded or recorded?
No. The tone is synthesized locally in your browser using the Web Audio API. Nothing is recorded or sent anywhere.