Things I’ve learned, published for the public benefit
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Online Tone Generator

Screenshot of the Online Tone Generator

I made an online tone generator based on the Firefox Audio API HTML5 Web Audio API. It’s basically a large logarithmic slider that allows real-time, smooth frequency changes.


  • Fine-tune the frequency in 1 Hz, 0.01 Hz and 0.001 Hz increments
  • Pick a music note from a list (added Sep 2014, revamped May 2016)
  • Increase/decrease the frequency by one octave (added Aug 2015)
  • Can change the frequency smoothly as you move the slider
  • Keyboard shortcuts (added Aug 2015)
  • Generate a link to a specific tone, so you can share it (added May 2016)
  • Choose sine/square/sawtooth/triangle wave (added Aug 2017)
  • Input frequency as a number (added Aug 2017)
  • Works well on Chrome, Firefox & Safari – including mobile devices (iOS, Android) – requires a browser with support for the Web Audio API.

There are other tone generators on the Web, but they are not as cool (if I do say so myself) and/or they require Java or Flash.

What can you use a tone generator for? You can do a science experiment with resonance, tune a musical instrument, test your new audio system (how low does it go?), test the limits of your hearing (I can hear virtually nothing above 18,000 Hz, even at maximum volume), or figure out your tinnitus frequency to better target therapy.

695 Comments so far

  • Chris Turner

    I used your fantastic app to test a power amp with an odd power supply issue.

    It worked very well.

    Thanks and Kudos.

  • Oystein Holter

    Great app!
    But do the different sine waves have the same volume? Some of them seem louder than others (in my ears, and with a Velleman db meter), and I wonder, is it just my speakers, or do the tones actually vary in volume.

  • Marxus

    Great tool for phreaking.

    You go sixes and i’ll go nines.

  • tom ralston

    Do you recommend or sell a speaker capable of outputting 40 hz? Especially one that can be attached to a PC. Even my stereo only speaker only goes down to 50hz. Just wondering, think you should sell one: -)

  • m

    hi mr s , this generator is amazing, i will show some support for your efforts. i have been working slofreggio tones. The octave shift is a great option. can you do binaural with this. i susspose if i open it up in 2 windows i could.
    Thanx for this great tool. wholeness and
    harmony friend

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