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.

740 Comments so far

  • Uar Battulayan

    Great! Playing with the frequencies up and down is very fun! Thank you so much!

  • Claire

    When I played 16 Hz (oxygen), I felt it all through the chakras. Not audible, but definitely can be felt. I wondered if playing this would help people with respiratory challenges. I was only able to send you $3 the other day because that’s all I had in Paypal. But this is a really valuable site and I’ll be back again. Thank you so much.

  • Robert Clark Jr

    Thanks for creating this. I am having fun with it. Paypal’d you $10.

  • Demetri Farquard the III

    I used it in class and got in trouble

  • TiviSu

    I listen the 40 Hz and after some time I have some headache or I feel some pressure in head… interesting…

  • Aaron S

    I am having issues getting any tone whatsoever to play on my iPhone 13. Is this designed to be compatible with iOS?

  • Kenan

    Hi Tomasz, thank you so much for your great work, it’s been so helpful when making EQ profiles for my iems, headphones and speakers. Only thing i wanted to share and ask is, is it possible for you to make the slider more precise especially in treble? if you could add an option to make the slider change the frequencies faster or slower, it’d be awesome! Because when fine tuning with EQ, sometimes i need more smooth and precise control over the frequency sweeps. Possible or not, thanks for your valuable time and effort you put into this project. I wanted to to donate for this project but paypal isn’t available in my country unfortunately 🙁 Best regards, take care.

  • James Tudehope

    I used two of your oscillators on different tabs to play for example 50 hz in the left ear and 51 hz in the right ear to create hemi-sync. The brain then zero beats the 1 hz in this case a delta wave. I alter the difference in the frequency to generate all the brain waves such as delta, theta, alpha, beta and gamma. I would love to see an adaptation to this program that allows a person to select one tone, send it only to your left ear, then select another tone and only send it to your right ear.

  • Overlord

    I always use your tool to match the crossover freq. between subwoofer and speakers. Never disappoints. Thanks!

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