Online Tone Generator – Play Tones and Hear Frequencies

What Is a Tone Generator?

A tone generator produces tones at any frequency you choose, measured in hertz (Hz). Everything here revolves around human hearing: you set a frequency, start playback and hear the tone instantly through your speakers or headphones. A function generator, by contrast, is a tool for electronics and measurement work that delivers electrical signals for circuits and test setups – there it is all about waveforms and voltages, here it is about audible sound.

Our online tone generator runs entirely in the browser and uses the Web Audio interface of your device. There is nothing to install and no account to create: open the page, choose a frequency, play the tone. It works on desktop computers just as well as on smartphones and tablets.

How to Play a Tone

When the page loads, a 440 Hz sine tone is preset – concert pitch A. Playing your own tone takes three steps:

1. Use the quick-select chips to pick a common frequency between 100 Hz and 15 kHz, such as the classic 1000 Hz tone used for testing.
2. Move the slider to adjust the frequency smoothly, or type the desired value as an exact number into the frequency field.
3. Start playback and adjust the volume as needed.

Important: always start at a low volume and raise it slowly – especially with headphones. Loud continuous tones can damage your hearing, and very low or very high frequencies often sound quieter than they really are.

Tones, Notes and Frequencies

Every musical note corresponds to a fixed frequency. The international tuning standard, concert pitch A, sits at 440 Hz – which is why it is also the default of this tone generator. During playback the tool shows you the note closest to the frequency you have set, so you can see at a glance which key on the piano your value corresponds to.

Doubling the frequency yields the same note one octave higher: 440 Hz becomes 880 Hz, the same A an octave up. Some reference values in equal temperament:

Tip: set any frequency and watch the note display – you will quickly develop a feel for how frequencies and notes relate.

The Human Hearing Range

Young, healthy ears cover roughly the range from 20 Hz to 20,000 Hz. Sounds below 20 Hz (infrasound) are felt as vibration rather than heard, while frequencies above 20 kHz (ultrasound) remain inaudible. With age, the upper hearing limit naturally declines: many adults barely perceive tones above 15,000 Hz, and later in life the limit is often considerably lower. These figures are guideline values and vary from person to person.

With the tone generator you can roughly explore your personal hearing limit by slowly raising the frequency. For a structured run through fixed frequency steps, try our hearing test – it is no substitute for a medical examination, though.

Typical Uses

A tone generator comes in handy in many everyday situations:

• Tuning instruments: play concert pitch A at 440 Hz as a reference for guitar, violin or wind instruments. If you would like to try alternative tunings, our page on 432 Hz has more information.
• Testing speakers and headphones: check bass response with low frequencies and treble with high ones. The 1000 Hz tone serves as a common reference for level comparisons.
• Hearing checks: find out which frequencies you can still perceive, or vividly demonstrate the difference between low and high tones in the classroom.
• Finding resonances: a slow sweep through the frequencies reveals objects in the room that vibrate along.

A continuous sine tone is also a great help when setting up a home cinema system or comparing two pairs of headphones, because it makes differences in individual frequency ranges clearly audible.

Which frequencies can I generate with the tone generator?

You can set any frequency in the audible range from 20 Hz to 20,000 Hz – via the quick-select chips from 100 Hz to 15 kHz, with the slider, or by entering an exact number. As a starting point, concert pitch A at 440 Hz is preset as a sine tone, so you hear a clean reference tone right away.

Is the online tone generator free?

Yes, the tone generator is completely free. You need neither a registration nor an installation: the tool runs directly in the browser on computers, smartphones and tablets. All features – quick select, slider, exact frequency input and note display – are available without restriction, and there are no hidden costs either.

Why can I not hear very high tones?

The upper hearing limit naturally declines with age – many adults barely hear frequencies above 15,000 Hz without any illness being involved. Technology plays a part too: small speakers, such as those in smartphones, often reproduce very high frequencies only weakly. To find out at which frequency your hearing gives up, take our hearing test.

What is the difference between a tone, a frequency and a note?

Frequency is the physical quantity: it states in hertz how often a sound wave oscillates per second. A tone is what you hear of it – the higher the frequency, the higher the tone sounds. A note is the musical name for a particular frequency, for example the note A4 (concert pitch A) for 440 Hz.