Online Tone Generator
Generate a pure tone at any frequency and waveform in your browser using the Web Audio API. Nothing is uploaded.
Pure browser JavaScript — uses the Web Audio API (OscillatorNode).
How to use this tool
- Pick a waveform (sine, square, sawtooth, triangle).
- Drag the frequency slider to your target Hz and set the volume.
- Click Play to hear the tone and Stop to silence it.
Generate a pure tone at any frequency and waveform in your browser using the Web Audio API. Nothing is uploaded.
How it works
The Online Tone Generator produces a continuous pure audio tone at any frequency you specify, using the browser's Web Audio API. Choose the frequency in hertz (Hz), select a waveform shape (sine, square, sawtooth, or triangle), set the volume, and click Play. The tone plays through your speakers or headphones with no audio file downloaded or uploaded.
A sine wave is the purest tone, with no harmonics -- it sounds like a tuning fork. Square, sawtooth, and triangle waves add harmonic content and sound more buzzy or reedy. Each waveform is useful for different purposes: sine for pitch reference, square for signal testing, sawtooth for synthesizer-style sounds.
Typical uses include tuning musical instruments by ear, testing speaker frequency response at different pitches, generating a reference pitch for singing or music practice, demonstrating acoustics concepts, and testing hearing at different frequencies. Standard pitches: A4 = 440 Hz, middle C = 261.63 Hz.
Worked example
Tune a guitar string to concert pitch A
- Set the frequency input to 440 Hz.
- Select sine wave for a clean, pure pitch.
- Set volume to a comfortable level.
- Click Play and listen while adjusting the guitar's A string until the pitches match.
Guitar's A string tuned to A4 = 440 Hz (concert pitch).
Common mistakes to avoid
- Setting volume too high when testing high-frequency tones, which can be uncomfortable or damaging to hearing.
- Confusing Hz with volume -- higher Hz means higher pitch, not louder sound.
- Not allowing audio permissions when prompted; the Web Audio API requires browser permission to play sound on some systems.
Key terms
- Hertz (Hz)
- The unit of frequency; one hertz equals one cycle per second. Human hearing ranges roughly from 20 Hz to 20,000 Hz.
- Sine wave
- The simplest waveform, a smooth oscillation with a single frequency and no harmonics. Sounds like a pure, clear tone.
- Harmonic
- A frequency that is an integer multiple of a fundamental frequency; harmonics give different waveforms their distinct tonal character.
Frequently asked questions
- Is the audio generated locally?
- Yes — the tone is synthesised in real time by the browser's Web Audio API. No sound files are downloaded and nothing is uploaded.