What is online tone generator?
A tone generator makes a pure sound at a chosen frequency. Musicians use it to tune instruments, audio engineers use it to test speakers and rooms, and students use it to hear how pitch changes with frequency.
The standard tuning note A4 is 440 hertz. Human hearing ranges from about 20 hertz to 20,000 hertz in young people, and the top end falls with age.
How to use the online tone generator
- Enter a frequency in hertz.
- Choose a waveform and set a low volume.
- Press Play, and press Stop when you are done.
How the online tone generator works
The tool uses the Web Audio API. An oscillator creates the waveform at your frequency and a gain control sets the volume, with a short fade in and out to avoid clicks. Nothing is recorded or uploaded.
Worked example
Common uses of the online tone generator
- Tuning instruments.
- Testing speakers and headphones.
- Physics and music lessons.
- Checking hearing range for fun.
- Finding resonance in a room.
Tips and common mistakes
Use headphones with care and keep the volume low.
Laptop and phone speakers may not reproduce tones below about 100 hertz.
Square and sawtooth waves sound harsher because they contain extra harmonics.
Background: what to know before you rely on it
Sound is vibration, and frequency is the number of vibrations per second, measured in hertz. Doubling the frequency raises the pitch by one octave. A sine wave contains only one frequency and sounds pure. Square, triangle and sawtooth waves add harmonics, which give instruments their character. Browsers can create these waves directly with the Web Audio API, which is why a tone generator no longer needs a plugin or an audio file. A tone generator is not a medical hearing test, because speakers and rooms change what you hear.
Private, free and fast
This tool runs entirely in your browser. What you type or choose is not uploaded to a server and is not saved after you close the page, which keeps it fast and private. It is free to use as often as you like. See more in all generators, or browse the full list of tools.
Frequently asked questions
What frequency is middle C?
About 261.63 hertz.
What is the best waveform for tuning?
A sine wave is the purest and easiest to match by ear.
Why can I not hear very high tones?
Hearing range falls with age, and many speakers cannot play above 16,000 hertz.
Is the sound safe?
Keep the volume low. Loud sound at any frequency can damage hearing.
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Results are for information and education. For legal, financial, medical or security decisions, check with a qualified professional. Do not use online generators for regulated draws or critical security keys.