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.

887 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.

    • Richard

      Response to James Tudehop’s comment. To play one frequency in one ear, you can access this generator in sessions and play each at the same time. using your headset to control mompo to one ear and the other . Or if that is difficult, try accessing this generator on 2 different laptops with an ear plug attached to each laptop playing the different frequency. Or at leasse with this idea in mind you have a building block on where you can start. good luck.

  • Overlord

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

  • Yeti

    Is there a way to get a sample in a digital file?

  • John Hear

    Meets all the 4 P’s
    Perfect to find resonant frequency with
    Perfect to test audio equipment with
    Perfect to test hearing perfect to fuck off anybody with
    Perfect to emulate that CRT whine that I wont hear anymore 20 years into the future (no with)

  • Rabitz/Angie

    Hey’.. Thank you for offering this online. I’ve been experimenting with the tones for deep healing. I feel the vibrations through my body. I’m keeping a journal as well. I just decided to donate $5. I’ll continue to donate each time I use this. Again thank you for giving something great to the world. Have a good weeekend. Sincerely, AD

  • Ghik

    I have high pitch hiss tinnitus with some random tones from time to time (mostly around 8khz and 12khz)

    When I match the frequency it suddendly disappear from my brain, giving me relief

    The high hiss is still there but at least I have fun kicking the tones out, so thank you 🙂

  • Paul

    Hi. I was looking for a non YouTube tones and found your page. I think it’s pretty cool, but I do have one issue with it.
    It doesn’t seem to audibly play on my iPad Air ? Though if I connect and listen through the headphone socket it works fine.‍♂️
    PS. Other audio works fine.
    PPS. Using Firefox


  • Ike

    This is a great tool for setting the subwoofer crossover frequencies on a home theater system. It would be even more useful if it would be able to specify any channel (FL, FR, C, SW, SL, SR) or combination of channels, perhaps with an on/off setting for each channel.
    On my system, the front, center and surround speakers have different frequency response and require different subwoofer crossover frequencies, and it’s difficult to adjust these individual crossovers while the other channels are active.

  • Max Rockbin

    By far my favorite tone generator. It would be really helpful if you added a phase dial or slider. For low frequencies especially, that’s very helpful.

    Maybe (?) also for tinnitus, since I think the phase of the tone makes a bit of difference to tinnitus sufferers.

  • stuart

    Thank’s for your great website
    Is midi input possible?

  • george t ramsey

    Is there an adjustment for decibel level in numbers?

  • Ethan Kim

    Thanks a lot for creating this incredible site! I found out I could hear 20154 Hz!

  • Hans Meyer

    This online tone generator is a great and “cool” instrument compared to other sound generators online for free, but the smallest step of sound volume (1%) is in this one already to high. For people who want to test their hearing to the finest and also the fine differencies in the hearing capability between both ears it should be possible to have more fine volume steps and a much lower sound volume at the beginning. Maybe you could think about it.

    With the best regards,


  • Bob

    Thanks this is a very useful website. The best online tone generator out there

  • Nate

    Wish the slider wasn’t packed in so close to the other buttons. No matter how careful i am, its only a matter of time before i brush the slider and blast the entire place with some ungodly frequency that sends the cat flying from the room.. It is frustrating only because otherwise this is the overall best tone generator i have found..

  • nickelelr

    Hey boss, love this website for everything.

    May I ask what the sample rate and bit depth of the tones are? Sometimes I run into a little clipping when there’s other stuff going on which might have to do with it having to convert to what my setting is.

    • Tomasz P. Szynalski

      The generator does not force any settings. It is left to the browser to decide. According to the spec, browsers should use the output device’s preferred settings. When it comes to clipping, the OS should mix sounds from different sources, reducing their volume to prevent clipping.

  • Samantha


    One of my students is using your generator for a science experiment with plants. I was wondering if you know the uncertainty on your generator? Like +/- .5 Hertz….something like that?

    Thank you!

    • Tomasz P. Szynalski

      It doesn’t really work like that. There’s always distortion, but that’s more like extra frequencies added to the main frequency. As you decrease the difference between two frequencies, I suppose at some point the whole audio pipeline (generator, DAC, amplifier, speakers, room response) will make them sound the same. Lots of factors here. But my guess is that would be < 0.01 Hz and would be hard to measure (with what equipment?). Anyhow, is it plausible that plants are sensitive to 5 Hz vs 5.01 Hz?? Even our ears (which are a very fine apparatus designed to resolve sounds) cannot detect such a difference. We are entering pseudoscience territory here.

  • Anita

    This website is amazing! I hope it keep exist! Thanks very much!

  • raph

    using this to calibrate my RTC oscillator, have you got any idea how accurate the generated frequencies are, you say its adjustable to +- 0.001Hz and i take this is across the spectrum so 1ppm at 1kHz? should be plenty good enough for less than a few seconds in a day which is what im aiming for.

    not exactly the intended purpose im sure but i have no calibrated test equipment let alone accurate standards and Liseau diagram lets me dial in and phase lock with the audio signal which doesn’t shift around one ive got it.

    I figure the RTC im my phone is GPS calibrated and the DAC would be dead on to way above the 1 or 2kHz im using so no issues there? Am i on atomic time?

  • Alwin

    Hello, is it possible to calculate the ballance difference L C R instead of in % in dB. This would help to identify the sensitivity difference between our left and right ear (using headphones)

  • Larry Sakurai

    I’d like to make a donation other than through PayPal.

  • Paul Dragon

    Any research done on frequency to destroy prions in the brain?

  • Porkupine




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