Hz Frequency Generator
Online Tone Generator
Play any frequency from 1 Hz to 20 kHz right in your browser. Type an exact Hz value or slide across the range, choose a waveform and channel, and share the tone with a link.
Hz
Nearest note A4 (+0¢)
202002k20k Hz
Channel
⚠️ Start at a low volume to protect your ears and speakers.
How to use the tone generator
- Set the frequency. Click the big number and type any value in Hz, drag the slider, or tap a preset. The slider is logarithmic, so low, mid and high frequencies each get equal room.
- Fine-tune. Use −1 / +1 to nudge by one hertz, or ÷2 / ×2 to jump a full octave down or up. The nearest musical note is shown under the number.
- Choose a waveform. Sine for a pure test tone; square, sawtooth or triangle for richer, harmonic sounds.
- Pick a channel. Play the tone in the left, right or both speakers — handy for checking each side separately.
- Press Play. You can change the frequency, waveform, channel and volume while the tone is playing.
- Share it. The page address keeps your settings — press “Copy link” to send the exact tone to someone else.
What can you do with a frequency generator?
- Test speakers and headphones. Step through low, mid and high frequencies to hear where your gear starts to struggle, or slowly move the slider to find a buzzing or rattling panel.
- Tune instruments. Play a reference pitch such as 440 Hz (A4) and tune by ear until the beating between the two sounds disappears.
- Explore your hearing. Raise a sine tone towards 15–20 kHz to find where it fades — or use the guided hearing frequency test.
- Learn and teach acoustics. Hear how doubling a frequency raises the pitch by an octave, and how waveforms with more harmonics sound brighter at the same pitch.
- Check a subwoofer. Play 20–80 Hz tones, or use the dedicated bass test with a low-frequency sweep.
Sine, square, sawtooth and triangle waves
Every waveform here plays the same fundamental frequency, so the pitch is identical — what changes is the mix of harmonics (multiples of that frequency) on top, which our ears hear as tone colour.
| Waveform | Sound | Good for |
|---|---|---|
| Sine | Pure, smooth, no harmonics | Speaker, hearing and acoustic tests |
| Square | Hollow, buzzy (odd harmonics) | Retro / chiptune sounds, clipping checks |
| Sawtooth | Bright, brassy (all harmonics) | Synth leads, harmonic demos |
| Triangle | Soft, flute-like (weak odd harmonics) | Gentle tones, synth pads |
Common test frequencies
| Frequency | What it is |
|---|---|
| 20 Hz | Bottom of human hearing — felt more than heard |
| 50 / 60 Hz | Mains hum frequency (EU / US); subwoofer range |
| 100 Hz | Bass check for regular speakers |
| 432 Hz | Alternative “A” tuning pitch |
| 440 Hz | Standard tuning pitch — the A above middle C (A4) |
| 528 Hz | Popular “Solfeggio” meditation frequency |
| 1 kHz | Standard reference test tone in audio engineering |
| 10 kHz | Treble / tweeter check |
| 15–17 kHz | Upper hearing limit for many adults |
| 20 kHz | Top of the typical human hearing range |
Want the reverse — the frequency and note of a sound you hear? Use the pitch detector. For telephone keypad tones, try the DTMF tone generator, to check left, right and the full range in one go, run the sound test, and to work out rhythm rather than pitch, tap the tempo with the tap BPM counter.
Frequently Asked Questions
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