Play any frequency from 1 Hz to 22 kHz with this free online tone generator. Choose a sine, square, triangle or sawtooth wave, glide through a frequency sweep, play short beeps, or switch to white, pink or brown noise.
Use it to test speakers, subwoofers and headphones, check your hearing range or tune an instrument, and download any sound as a WAV file. Nothing to install.
Online Tone Generator
Choose a frequency and press Play. Start at a low volume, especially with headphones.
Ready. With a button focused, the arrow keys change the frequency by 1 Hz (Shift: 10 Hz).
Sound is generated in your browser; nothing is uploaded. Very high and very low frequencies may be inaudible because of your speakers or hearing, not the tool. Listening to loud tones, especially above 10 kHz on headphones, can be uncomfortable or harmful. On iPhone, turn off silent mode if you hear nothing.
Related Tools
- Frequency Analyzer
See the frequencies in any sound, live from your microphone.
- Online Hearing Test
Check which frequencies you can hear in each ear.
- Sound Decibel Meter
Measure how loud your speakers or room are in dB.
- Microphone Test
Check that your mic picks up the test tone.
- Background Noise Test
Make sure the room is quiet before you test.
- Audio Wavelength Calculator
Turn any frequency into its wavelength in air.
How to Use the Tone Generator
- Turn your device volume down, then press Play. The tool starts with 440 Hz, the note A4.
- Type a frequency, drag the slider, or use −1 / +1 for fine steps and ÷2 / ×2 to jump an octave down or up. With a button focused, the arrow keys also move 1 Hz (Shift: 10 Hz).
- Pick a waveform, and raise the volume slowly until the tone is comfortable.
- Switch Mode for a sweep, repeating beeps or noise. Use Channel to send sound to the left or right side only.
- Set Stop after if you want the sound to end by itself, and use Copy link to share exactly the same settings.
Sine, Square, Triangle and Sawtooth Waves
Every waveform repeats at the frequency you set, but each adds a different set of higher harmonics, which changes how it sounds.
| Waveform | Sound | Harmonics | Good for |
|---|---|---|---|
| Sine | Pure, smooth tone | None: a single frequency | Hearing checks, speaker and sub tests, tuning, calibration |
| Square | Hollow, buzzy, like an old video game | Odd harmonics (3rd, 5th, 7th…) at 1/n strength | Checking rattles and distortion, retro sounds |
| Triangle | Soft, flute-like | Odd harmonics, fading fast (1/n²) | A gentler alternative to a sine |
| Sawtooth | Bright and brassy | All harmonics at 1/n strength | Synth sounds, testing a wide range at once |
The square wave is level-matched so it doesn’t jump out louder than a sine at the same volume setting.
Frequency Sweeps, Beeps and Noise
- Sweep glides from a start frequency to an end frequency over the time you choose. The logarithmic setting spends the same time on every octave, which matches how we hear; linear moves the same number of hertz each second. The 20 Hz–20 kHz sweep button runs the full audible range.
- Beep / pulse repeats a tone with gaps between, for example 200 ms on and 800 ms off. Pulses make it easier to hear where a sound comes from and to spot buzzes.
- White noise has equal energy at every frequency and sounds like a hiss. Pink noise has equal energy per octave, so it sounds more balanced and is the standard signal for tuning speakers and rooms. Brown noise is deeper still, like a low rumble or distant waterfall.
Useful Test Frequencies
| Frequency | What it is | Use it to |
|---|---|---|
| 20 Hz | Lower limit of human hearing | Check how deep a subwoofer really goes |
| 50 Hz / 60 Hz | Mains hum (50 Hz in Europe, Asia and Africa; 60 Hz in North America) | Identify electrical hum in a recording or system |
| 100 Hz | Bass | Test small speakers and phones; many can’t play much lower |
| 440 Hz | A4, concert pitch (ISO 16) | Tune instruments and check pitch |
| 1 kHz | The standard reference tone | Set levels; sound level calibrators play 1 kHz |
| 10 kHz | High treble | Check tweeters |
| 15–17.4 kHz | Upper hearing that fades with age | Quick high-frequency hearing check |
| 20 kHz | Upper limit of human hearing | Test the top end of speakers and headphones |
Frequency is how high or low a sound is, not how loud it is; loudness is measured in decibels. dB vs Hz explains the difference, and a 1 kHz tone is also used to calibrate a microphone against a sound level meter. Real calibrators play 1 kHz at 94 dB, a sound pressure level of 1 pascal (you can check that with the SPL converter).
Test Speakers, Subwoofers and Headphones
- Left and right: set Channel to Left only, then Right only, to confirm that each speaker or earcup is wired correctly.
- Subwoofer: sweep from 20 Hz to 120 Hz at a moderate volume. Note where the bass fades out and listen for rattles or buzzing at particular frequencies.
- Speakers: a slow full-range sweep reveals weak spots, sharp peaks and distortion. Laptop and phone speakers usually can’t reproduce the deepest bass, which is normal.
- Headphones: start at a very low volume. High tones can sound much louder in headphones than on speakers.
To see what your speakers actually produce, play a sweep on one device and watch it with the Frequency Analyzer (in Related Tools) on another.
How High Can You Hear?
Human hearing covers roughly 20 Hz to 20 kHz, but the top end drops with age and noise exposure. Many adults can’t hear much above 15–17 kHz, and the 17.4 kHz tone is often described as audible mainly to teenagers. If you can’t hear a very high or very low tone, the limit may be your speakers or headphones rather than your ears, so try another device before drawing conclusions.
This is a quick check, not a medical test. Keep the volume low: loud tones at any frequency can damage hearing, and the risk grows with level and time (see the safe noise levels chart and is 85 dB dangerous?, or work out a safe listening time with the noise exposure calculator).
Tone Generator, Signal Generator or Oscillator?
An online tone generator is an audio signal generator: an oscillator in your browser creates the waveform, and your device plays it through its sound card. That makes it ideal for audio work, but it is limited by your hardware. The highest possible tone is half the sample rate (the Nyquist limit): 22,050 Hz at 44.1 kHz and 24,000 Hz at 48 kHz. The tool shows the sample rate your device uses when you press Play.
Downloaded WAV files are 44.1 kHz, 16-bit stereo, with a peak level of −6 dBFS, which leaves headroom so they don’t clip. dB vs dBFS explains digital levels, and the decibel units guide covers the rest. A lab function generator is still the right tool for electronics, where you need a voltage output rather than sound.
Frequently Asked Questions
Is this tone generator free?
Yes. It’s free, needs no download or sign-up, and works in current browsers on phones, tablets and computers. Sound is generated on your device; nothing is uploaded.
Can I download the tone as an audio file?
Yes. Choose a length of 5, 10 or 30 seconds and press Download WAV. Sweeps use their own duration (up to 60 seconds). The file keeps your waveform, mode and channel settings.
Why can’t I hear anything on my iPhone?
On iPhone, browser audio can be muted by the silent switch. Turn off silent mode, raise the volume a little and press Play again. Very low tones may also be too deep for a phone speaker.
What frequency is middle C?
Middle C (C4) is about 261.63 Hz, and A4, the note orchestras tune to, is 440 Hz. The tool shows the nearest note and how many cents sharp or flat any frequency is.