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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.


457 Comments so far

  • David Marshall

    I am 66 years old and have tremor in my hands. Not nice. I have set the tone down to 40 Hz. and it has reduced the tremors nearly down to nothing. I combine with other tones at 432 Hz. I would recommend trying this with anyone that has these sort of issues.
    I play for a couple of hours each day. I will continue to do this as it is very relaxing as well as beneficial.

    Thank you

  • Antonio Dembech

    Will be fantastic to have two different frequencies. One on the left speaker and one on the right speaker. So we can hear the phisics beats.

  • Jes Vesper

    Dear Tomasz,

    Thank you so much for enabling me to listen to 40 herz. It has given me back things I thought I already had lost for ever. I am in the early stages of Huntington’s, a hereditary illness, that has similarities with Alzheimer’s. Listening to your 40 herz for 45 minutes every other day, has lifted the permanent fog in my head; given me back a lot of words; returned my energy; given me back part of my short term memory and cognition. It’s nothing short of a miracle! On top of all that I feel happier.
    So thank you and spread the word!


    • Tomasz P. Szynalski

      That’s great! Thank you for sharing such a positive experience. When did you start listening to 40 Hz?

      • Jes Vesper

        I started a month ago. The fog in my head lifted immediately after one session, the other results grew more slowly. I have to play the piano a lot for my profession, even my playing has become easier.
        I cannot tell you how thankful I am!


  • Jerry Bies

    Which 40 Hz. tone is used Sin, Square, Triangle or Sawtooth for these results?

    • Jes Vesper

      Hi Jerry,

      I use the sawtooth variation without any real reason behind my choice….


    • Sal

      I use the Saw Tooth, as it seems to provide more of a clean “PULSE” than the other options. It may not seem as pleasant, but I think it might be more effective.

  • Andruhan4eK

    I have been using your program for a long time, I am from Russia, I am very grateful to you, your program and website often help me out.
    I wish you good health and good mood)))

  • dude

    Can this damage your hearing? My friends do it all the time. I can hear the Hz. that others can’t. If I listen to too much of this, will I not be able to have that special hearing superpower? 🙂

    • Tomasz P. Szynalski

      Not an expert, but I think it might damage your superpower if the volume is too high. Remember that for these high frequencies, even if you can barely hear it, the volume can still be objectively quite high (it would show a lot of decibels if you measured it with a meter).

  • J

    I think it would be cool if you could reverse the wave so you could noise cancel something without needing some active noise canceling device.

  • Tom

    Does anyone have an explanation as to why when I use an Radio Shack SPL meter to measure the dB SPL that it increases as the frequency increases? Note this has nothing to do with my own perceived loudness of the tone. For example, I have the meter set to C weighting and slow. I then choose 500 Hz and set the my amplication so the meter measures 60 dB when a set length from the speaker. I then change the frequency to 5000 Hz and the meter measures some 25 dB higher. I realize the speakers will not have a flat response but I ran this same little test on a few different speakers as well as directly out of my phone speaker with the meter an inch away and observed the same phenomena. Does this have to do with sound waves of the higher frequencies decaying slower somehow as they move through that little bit of air or with feedback as the waves bounce off the meter and back around, etc. Or is my meter faulty?

    Great site and tool btw.

    • Tomasz P. Szynalski

      C weighting should not produce a difference between 500 Hz and 5 kHz. My guess is that you’re measuring always in the same spot, which causes constructive interference with the same wave from (1) your other speaker or (2) some nearby surface. Try moving the meter 2-3 cm in various directions.

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