Generate a pure tone from 20 Hz to 20 kHz online: sine, square, sawtooth, or triangle, with left/right balance and WAV download. Free.
The tone generator plays a continuous tone at any frequency from 20 Hz to 20 kHz. Pick a sine wave for a pure tone, or square, sawtooth, or triangle for a harmonically richer one; type an exact frequency or sweep the slider, which is logarithmic so it follows how pitch is heard. You can push the tone to the left or right channel and download it as a WAV file of 5 to 60 seconds.
People use it to check speakers and headphones, find a rattle or a room resonance, test the left and right channels, produce a reference pitch, or see roughly how high they can hear. The tone is generated in your browser — there is no audio file behind it. Start quiet: pure tones can be louder than they sound, and very low or very high ones can stress small speakers and ears. It is not a medical hearing test. The audible frequency range explains what the numbers mean.
Common uses are checking that speakers or headphones reproduce low and high frequencies, finding the frequency that makes something in a room rattle or resonate, confirming the left and right channels are wired correctly, and producing a reference pitch for tuning. It also gives a rough idea of the highest frequency you can hear, though it is not a calibrated hearing test.
A sine wave contains one frequency only, so it is the purest tone. Square and triangle waves add odd harmonics above that frequency, strongly in the square wave and weakly in the triangle. A sawtooth adds both odd and even harmonics and sounds the brightest and buzziest of the four.
At a moderate volume, yes. Start with the level low and raise it gradually, because a pure tone can be louder than it seems, particularly above 2 kHz. Avoid long, loud playback of very low tones on small speakers and of very high tones on headphones, since both can cause damage before they sound uncomfortable.
Yes. Choose a length of 5, 10, 30, or 60 seconds and press Download to save a WAV file with the current frequency, waveform, volume, and balance. The file is rendered in your browser at 48 kHz, and the first and last 10 milliseconds fade in and out so it starts and ends without a click. The filename records the frequency, waveform, and length, for example tone_440hz_sine_10s.wav.
Usually because of the speaker rather than the tone. Phone and laptop speakers reproduce very little deep bass, so the lowest settings can be faint or silent on them, and many small speakers and earbuds also fall off at the top of the range. The highest frequency a person can hear also tends to drop with age. The generator covers 20 Hz to 20 kHz either way, so do not keep turning the volume up to chase a tone you cannot hear.