Unfortunately, it looks as though either your browser does not support JavaScript or that JavaScript is currently disabled. In order for this calculator to work properly, please enable JavaScript in your browser. Let me know if you encounter any difficulties. On Mac systems, it should now work correctly (I still can’t test it though as I don’t own a Mac). Installing the ttf unifont package should fix this problem (from a terminal window, run: sudo apt install ttf-unifont). On some Ubuntu/Debian Linux systems it’s possible that the waveform graphics may display incorrectly. I’ve added a choice of waveforms for playback (because I can! 😉 ) but do bear in mind that since the default sine wave consists of only the fundamental it is the only pure waveform all the others contain overtones (or harmonics) of one sort or another: It’s also useful for cases where you might need to calculate an exact frequency for “surgical” EQ-ing. You can press Play to hear the note at the frequency displayed and you can change the pitch, waveform and volume whether or not sound is playing. It also displays the MIDI note name derived from any of the 3 common standards Middle C = C3, C4 or C5 (default is C4). It can display frequencies based on any user-defined reference pitch (for A above middle C) between 390 – 490 Hz (default is A = 440 Hz). Since it is able to play sound, it can also be used as an online tuning fork. This utility calculates the audio frequency and MIDI note name from any MIDI note number.

Midi note number chart octive