🔊 Online Tone Generator
Play a pure tone at any frequency from 1 Hz to 20 kHz. Sine, square, triangle or sawtooth, left/right channel test, and a frequency sweep.
Nearest note: A4
Start with your device volume low — high-frequency and square-wave tones can be loud and unpleasant, and prolonged loud tones can damage hearing.
What Online Tone Generator Does
This online tone generator plays a steady tone at any frequency from 1 Hz to 20,000 Hz, generated live by your browser’s audio engine. Type an exact value or drag the logarithmic slider, and the pitch glides smoothly while it plays. Four waveforms are available — sine, square, triangle and sawtooth — and the tone can be sent to both speakers, the left only or the right only.
Switch to Frequency sweep to glide from one frequency to another over a set time, linearly or logarithmically. A 20 Hz to 20 kHz sweep is a quick way to check the frequency range of speakers and headphones, find rattles and resonances, or hear where your own upper limit of hearing lies. The current frequency is shown as it plays.
For musicians, the nearest note and its offset in cents are shown for any frequency, and presets include A4 at 440 Hz, the usual tuning reference.
How to Use Online Tone Generator
- Enter a frequency or pick a preset such as A4 440 Hz or 1 kHz
- Choose a waveform, channel and a low volume
- Press Play and adjust the frequency live
- Switch to Frequency sweep to glide between two frequencies
- Press Stop when done
Formula Used by Online Tone Generator
Frequency and musical pitch
Note number = 69 + 12 × log₂(f ÷ 440 Hz); each octave doubles the frequency
Worked example
261.63 Hz
- log₂(261.63 ÷ 440) = −0.75
- 69 + 12 × (−0.75) = 60
Result: Note 60 = middle C (C4).
Wavelength in air
λ = speed of sound ÷ f ≈ 343 m/s ÷ f at 20 °C
Worked example
1,000 Hz
- 343 ÷ 1000
Result: About 34 cm — low tones are meters long, which is why small speakers struggle with bass.
Useful Test Frequencies
| Frequency | What it is used for |
|---|---|
| 20–60 Hz | Subwoofer and deep-bass check; many small speakers are silent here |
| 50 / 60 Hz | Mains hum (50 Hz in Europe and much of Asia, 60 Hz in North America) |
| 440 Hz | A4, the standard tuning pitch |
| 1,000 Hz | Standard reference tone for audio levels |
| 10,000 Hz | Treble check |
| 15,000–17,000 Hz | Often inaudible to adults; hearing at the top of the range declines with age |
How to Read Your Result
Testing speakers and headphones
Use a sine wave at low volume and a slow logarithmic sweep. Listen for the frequency where sound first appears at the bottom, buzzing or rattling in the middle, and where it fades at the top. Repeat on the left and right channels separately to compare them.
Where did the tone go?
If a high tone vanishes, it may be your hearing, your headphones, or both — laptop and phone speakers often stop well before 20 kHz. Try a second pair of headphones before drawing conclusions, and never raise the volume to “find” a tone you cannot hear.
Limitations & Accuracy Notes
- Output depends on your sound card, speakers and system settings; some devices apply processing that changes the tone.
- The browser generates audio at your device’s sample rate, commonly 44.1 or 48 kHz, which limits the highest clean frequency.
- This is not a calibrated hearing test. For hearing concerns, see an audiologist.