Online Tone Generator

What is an online tone generator?

An online tone generator produces a pure audio tone at any frequency you choose, from 20 Hz up to 20,000 Hz. Pick a frequency, press play, and your browser plays the tone through your speakers or headphones. There is nothing to install and no account to create — the tone is generated locally on your device in real time.

You can use a tone generator to tune an instrument, test speakers or headphones, check your hearing, or simply hear what a specific frequency sounds like. The generator covers the full range of human hearing, so you can explore everything from a deep 20 Hz rumble to a piercing 20 kHz whine.

Unlike a phone app or desktop software, a web-based tone generator needs no download, no installation, and no account. Open the page, set a frequency, and press play. It works on desktop and mobile, and because the tone is synthesized locally with the Web Audio API, it keeps working even without an internet connection after the page loads.

The four waveforms, explained

Sound waves come in different shapes, and each shape has a distinct character. This generator offers four waveforms, so you can hear exactly how each one changes the sound.

Sine wave

A sine wave is the purest sound there is — a single frequency with no harmonics. It sounds smooth and clean, which is why it is the standard for tuning references (440 Hz A4) and hearing tests. If you want a stable, uncolored pitch, use sine.

Square wave

A square wave switches instantly between two levels, producing a hollow, slightly harsh tone rich in odd harmonics. Square waves are the classic sound of 8-bit chiptune music and are also useful for testing how speakers handle fast transients.

Triangle wave

A triangle wave ramps up and down smoothly, giving a tone that is softer than a square wave but still contains harmonics. It sounds warm and is often used for bass lines in synthesis. It is a good middle ground between the purity of sine and the edge of square.

Sawtooth wave

A sawtooth wave rises smoothly and snaps back down, containing all harmonics. It sounds bright and buzzy — the classic lead sound of analog synthesizers. Use sawtooth when you want a tone with maximum harmonic content and edge.

Common frequencies and what they are for

• 440 Hz — the standard A4 tuning reference for instruments.
• 432 Hz — an alternate tuning pitch favored by some musicians.
• 528 Hz — an alternate tuning tone, sometimes called the “love frequency”.
• 1 kHz — the standard test tone for speakers and audio equipment.
• 40 Hz — useful for checking bass response and subwoofers.
• 20 Hz — the lower edge of human hearing, good for testing deep bass.

Tap any preset in the tool above to jump straight to a common frequency, then adjust with the slider or number input for a precise value.

Ways people use a tone generator

Tuning instruments

Play a 440 Hz A4 reference and tune your guitar, violin, or piano string to match it. Musicians also use 432 Hz as an alternative reference pitch. Because the tone is a pure sine wave, your ear can hear even the smallest difference in pitch against your instrument.

Testing speakers and headphones

Play a 1 kHz tone to confirm both channels are working, a 40 Hz tone to check bass response, or run a full sweep from 20 Hz to 20 kHz to find rattles and distortion. A blown speaker will often buzz or rattle at specific frequencies, which makes a tone generator a fast and free diagnostic tool.

Checking your hearing

Pure tones are the standard way to test hearing. Most people hear from roughly 20 Hz to 20 kHz, but the upper limit drops with age. If a 20 kHz tone is silent to you but audible to someone younger, that is completely normal — it does not mean your hearing is damaged.

Sound design and synthesis

Sine, square, triangle and sawtooth waves are the four building blocks of synthesis. Auditioning each waveform in isolation is the fastest way to train your ear to recognize them in music and sound design. Switch between the waveforms in the tool and notice how the character of the sound changes even at the same frequency.

Science and education

Teachers use tone generators to demonstrate frequency, pitch and waveforms. A visible waveform on the canvas plus an audible tone makes the abstract idea of a sound wave concrete, and lets students connect what they see to what they hear.

Keep it safe for your ears

Pure tones concentrate all their energy into a narrow frequency range, so they feel louder and harsher than music at the same volume. Follow three simple rules: start at a low volume and raise it slowly, avoid long sessions with headphones, and never play loud tones close to your ears. If a tone causes discomfort, ringing, or pain, stop immediately.

How to use it

1. Start low.
2. Press play.
3. Drag the frequency.
4. Change the waveform if you want a different edge.
5. Copy the link or save a WAV when you find the tone.

Common questions

What is a tone generator used for?

A tone generator produces reference tones for tuning instruments, testing speakers and headphones, checking hearing, or experimenting with sound. Because you can set any frequency, it doubles as a precise frequency generator.

Is this the same as a frequency generator?

Yes. Pick a frequency, press play, hear the tone. A frequency generator and a tone generator are the same thing in practice — both produce a tone at a frequency you control.

What is the difference between sine and square waves?

A sine wave contains a single frequency with no harmonics and sounds smooth. A square wave contains odd harmonics and sounds hollow and buzzy. Use sine for tuning and tests, square for chiptune-style tones and transient tests.

Can I use headphones?

Yes, but start at a very low volume. Pure tones can feel sharp very quickly, and listening at high volume can damage your hearing.

Why does the browser require a click before sound plays?

Browsers block audio from playing automatically to prevent surprise sounds. A click tells the browser you actually want sound, so the first play must be started by you.

Can I save the tone as a file?

Yes. Use the Save WAV button to download a five-second WAV file of the current tone, or copy the link to share the exact frequency and waveform you set.