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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.

553 Comments so far

  • Rizwan

    Please add a dB control

  • Jes Vesper

    Hi Tomasz,

    Since about one week, the ‘ringing’ sound that stayed for a very short time (I think thirty to forty seconds) after my session of listening to 40 Hertz, doesn’ t go away anymore….. It went from only a few seconds after the listening session to permanent. This leaves me in a terrible dilemma, since I am a music teacher and therefore can’t risk my hearing, but I also need the 40 Hertz sessions for my brain to function better. I tried turning down the volume, but that doesn’t help. I use earphones of a very good quality. Do you have any ideas what I could do? Could I have damaged my hearing?
    Kind regards, Jes

    • Tomasz P. Szynalski

      Permanent hearing damage is unlikely if you’ve been listening at a reasonable volume. You could try switching to a sine wave — that doesn’t contain high harmonics which are the most dangerous.

  • Jes Vesper

    Hi Tomasz,

    Thanks you so much for your advice!
    I’ll switch to the sine tone!

    Kind regards Jes

  • nl

    send you a few sawbucks soon. nice work. genius workable site.

  • Prof. Peter Kiefer

    Super tool, thank you. It would be great, if one could download the frequencies…

  • Abraham

    I think this is a great tool for irritating people, and i know that isnt what it is for, but its funny to watch people wonder where the noise is coming from!

  • Gimlao

    Using Chrome and Safari on iOS 14, it’s showing this text :

    ” The Online Tone Generator won’t work because your browser does not fully support the Web Audio API. You can use the Online Tone Generator if you install a recent version of Firefox, Chrome or Safari. ”

    But actually, everything is working fine, so it should not show this text on top. =p

  • Hugh Crosthwait

    Is there any difference between the sound produced by your generator and commercially available devices? Also do you know where 40 hertz light generators may be available?
    Thank you
    Hugh Crosthwait

  • Antonino Fratta

    Thank you Tomasz,
    For the very first time, in my experience a sampled (digital) generator has completely replaced the analog (old HP) thanks to fine tune capability, adding exact frequency knowledge without its measure.
    And I learned about frequency therapies.
    During these corona crimdumb months your Tone G. and name have been always ON my desktop, available for my experiments, testing acoustics after decades from my teen passion (and finally adopting drivers put aside 44 years ago). Wonderful. I also restored drivers made in the ’50s, actually working in a bass-horn for my joy in listening. Light cones match better.
    Hope you are well and enjoying with all your beloved and homely.

  • Lorraine Murji

    I’d love to have this version as an app. I’d buy it then. Any possibility ?

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