Online Tone Generator
Play a steady tone at any frequency, or pick a note. Change the pitch while it plays, switch waveform, and copy a link that opens the same tone.
Nearest note A4 at A4 = 440 Hz
Waveform
Concert pitch (A4)
Changes the note buttons and the nearest-note readout. 440 Hz is the modern standard; 442–443 Hz is common in European orchestras.
Play a note
Guitar strings, standard tuning
What You Can Do With a Tone Generator
- Tune by ear. A steady sine at 110 Hz is the A string. Play the string against it and listen for beats: a wobble that slows down as the two pitches get closer and stops when they match.
- Hold a reference or drone. Leave an A or a D running and practise scales over it to hear how each note sounds against the root — the same idea as the drone in the scale explorer.
- Check speakers and headphones. Sweep the slider from low to high and listen for rattles, buzzing, or the point where the bass disappears.
- Find your hearing range. Slowly raise the frequency at a modest volume and note where the tone fades out. This is a curiosity, not a medical test.
- Train your ear. Play two notes a semitone apart, or nudge a tone by 1 Hz, and find how small a difference you can hear. The ear trainer and daily challenge take this further.
How Notes Map to Frequencies
Modern Western music fixes A4 — the A above middle C — at 440 Hz and divides every octave into twelve equal semitones. Each semitone multiplies the frequency by the twelfth root of two, about 1.0595, so twelve of them double it: A5 is 880 Hz and A3 is 220 Hz. The note buttons and the nearest-note readout use exactly this formula, at whichever concert pitch you choose.
| Pitch | Frequency at A4 = 440 |
|---|---|
| Low E string (6th), standard tuning | 82.41 Hz |
| A string (5th) | 110.00 Hz |
| Middle C | 261.63 Hz |
| Concert A — the tuning reference | 440.00 Hz |
| High E string (1st) | 329.63 Hz |
| Top of a 24-fret guitar (E6) | 1318.51 Hz |
Every alternate tuning is just a different set of these numbers. The guitar tunings chart lists the frequency of every string in every tuning the site supports.
The Four Waveforms
A sine wave is a single frequency with nothing else in it, which makes it the cleanest reference but also the quietest on small speakers. A triangle adds faint odd harmonics and sounds like a soft flute. A square wave has strong odd harmonics and sounds hollow and buzzy, like an old video game. A sawtooth has every harmonic and is the brightest of all — the raw sound behind many synthesiser patches. The generator turns square and sawtooth down automatically so switching waveform does not make you jump.
Protect Your Hearing
A pure tone is more tiring to listen to than music, and the louder waveforms can be harsh on headphones. Start with the volume low, raise it gradually, and take breaks. Be especially careful when you cannot hear a tone at all: very high frequencies can still be loud enough to cause harm, and very low ones can damage small speakers at full volume.
Frequently Asked Questions
How accurate is the frequency?
The tone is generated by your browser's audio engine, which is digitally exact: ask for 440 Hz and the oscillator runs at 440 Hz. What you hear can still be coloured by your speakers, but they cannot change the pitch. The readout shows two decimal places because that is the step the input accepts.
Which waveform should I use?
Sine for a pure reference pitch, tuning by ear, or hearing tests — it has no harmonics, so there is only one pitch to hear. Triangle is still soft but a little easier to hear on small speakers. Square and sawtooth are bright and buzzy because they are full of harmonics; they are easier to hear on a phone speaker and useful for testing speakers, but a poor choice for judging pitch.
Why can't I hear very low or very high tones?
Low tones: phone and laptop speakers are physically too small to move much air below about 100 Hz, so a 40 Hz tone may be almost silent on them. Use headphones. High tones: most adults lose hearing above 12–16 kHz with age. In both cases, do not turn the volume up to compensate — when you switch back to a frequency you can hear, it will be very loud.
Can I use it to tune my guitar?
Yes. Press the button for a string, play the open string, and adjust until the beating — a slow wobble in volume — disappears. That is tuning by ear against a reference. For most people a tuner is faster and more precise, which is why the guitar tuner on our home page listens to your strings through the microphone instead.
What does the concert pitch setting do?
It moves every note. With A4 set to 432 Hz, the A button plays 432 Hz and every other note shifts by the same ratio. It also changes the nearest-note readout, so 432 Hz shows as A4 with no offset rather than A4 about −32 cents.
Does the tone keep playing if I switch tabs?
Yes, until you press Stop or close the page, so you can leave a reference or drone running while you play. Leaving the page always stops it.