Online tone generator
Any frequency from 1 Hz to 20 kHz, with four waveforms. Drag the dial, type an exact value, or nudge it one step at a time.
Frequency sweep
Glide smoothly from one frequency to another. Press I lost it the moment the tone disappears to see roughly where your hearing (or your speaker) tops out.
Most young adults hear up to about 17–20 kHz; the upper limit falls with age. This is not a medical hearing test, and laptop and phone speakers often can’t play the extremes.
Frequency to note converter
Waveforms, briefly
Sine is a single frequency and nothing else: the purest, softest tone. Triangle adds faint odd harmonics and sounds like a gentle flute. Square is rich in odd harmonics (buzzy, clarinet-like), and sawtooth contains every harmonic, the bright raw sound of a synthesizer. Square and sawtooth are played quieter here because they sound much louder at the same level.
Handy reference frequencies
| Frequency | What it’s used for |
|---|---|
| 50 Hz | Mains hum (Europe); 60 Hz in the Americas |
| 100 Hz | Sub-bass speaker check |
| 165 Hz | Speaker water-eject tones |
| 440 Hz | Concert A (ISO 16) |
| 1,000 Hz | Standard audio test tone |
| 8,000 Hz | Hearing drops here first with age |
| 17,400 Hz | The “mosquito” tone many adults can’t hear |
Checking your ears rather than your speakers? Try the step-by-step online hearing test.
Protect your hearing: high frequencies and square waves are fatiguing. Keep test tones brief and quiet.
Note frequencies (A4 = 440 Hz)
| Note | Octave 2 | Octave 3 | Octave 4 | Octave 5 |
|---|---|---|---|---|
| C | 65.41 | 130.81 | 261.63 | 523.25 |
| C♯ | 69.3 | 138.59 | 277.18 | 554.37 |
| D | 73.42 | 146.83 | 293.66 | 587.33 |
| D♯ | 77.78 | 155.56 | 311.13 | 622.25 |
| E | 82.41 | 164.81 | 329.63 | 659.26 |
| F | 87.31 | 174.61 | 349.23 | 698.46 |
| F♯ | 92.5 | 185 | 369.99 | 739.99 |
| G | 98 | 196 | 392 | 783.99 |
| G♯ | 103.83 | 207.65 | 415.3 | 830.61 |
| A | 110 | 220 | 440 | 880 |
| A♯ | 116.54 | 233.08 | 466.16 | 932.33 |
| B | 123.47 | 246.94 | 493.88 | 987.77 |
Questions people ask
What frequencies can this tone generator play?
Anything from 1 Hz to 20,000 Hz, in sine, triangle, square or sawtooth. Whether you hear the extremes depends on your ears and your speakers.
Why can’t I hear very low tones?
Human hearing starts around 20 Hz, and phone or laptop speakers struggle below 100–300 Hz. Use headphones or a subwoofer for bass tests.
Can I use it to tune an instrument?
Yes. A4 is 440 Hz (or 432 Hz if you prefer that tuning). The frequency box accepts decimals, so you can type the exact pitch of any note.
How do I find which note a frequency is?
Use the converter on this page: it gives the nearest note in equal temperament and how many cents sharp or flat the frequency is, for A4 = 440 Hz or any other reference.
Can I use this as a hearing test?
The sweep gives a rough upper limit. For a step-by-step, ear-by-ear check, use the hearing test page.
Can a tone generator remove water from my phone speaker?
Low tones around 150–165 Hz are widely used to push droplets out of a speaker grille by vibration. It sometimes helps; it won’t fix a damaged speaker.