Frequency Detector
FREE
Measure sound frequency in real time from your microphone. See live Hz, min, max, and average with a waveform view—free in your browser.
440Hz
A4Frequency
1 Hz20,000 Hz
Volume50%
Speaker BalanceCenter
LCenterR
Waveform
Select Note
OctCC#DD#EFF#GG#AA#B
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To protect your hearing, do not listen to very low frequencies (below 20 Hz) or very high frequencies (above 10,000 Hz) at high volumes for extended periods.
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Online tone generator — play any frequency or musical note
Generate pure sine, square, sawtooth, and triangle wave tones online. This free tone generator lets you play any frequency from 1 Hz to 20,000 Hz. Adjust volume and speaker balance. Select musical notes from the grid. Test speakers, tune instruments, or match tinnitus frequency. No download required.
What is an online tone generator (frequency generator)?
An online tone generator (also called a frequency generator, Hz player, pitch maker, or tone creator) is a tool that produces pure audio tones at specific frequencies measured in Hertz (Hz). This free web-based tone generator uses the Web Audio API to generate precise sine, square, sawtooth, and triangle waveforms from 1 Hz to 20,000 Hz directly in your browser. You can use it to test speakers and headphones, tune musical instruments by ear, match tinnitus frequencies, demonstrate acoustic beat phenomena, or conduct hearing tests. Unlike downloadable software, this online frequency generator requires no installation—just press play and adjust the frequency slider to hear any tone instantly.
Tone generator features
A complete online frequency generator with multiple waveforms, note selection, and precise Hz control.
Play any frequency from 1 Hz to 20,000 Hz
This tone generator covers the full human hearing range. Use the frequency slider or the up/down buttons to select any frequency from 1 Hz to 20,000 Hz. The current Hz value is displayed in large digits for easy reading.
Four waveform types — sine, square, sawtooth & triangle
Switch between sine (smooth and clean), square (buzzy and rich), sawtooth (harsh and distorted), and triangle (bright and breathy) waveforms. Each waveform type produces a distinct tone character for different uses—from pure test tones to musical sound design.
Musical note selection grid
Pick any musical note from the grid spanning C0 to B8—every note across 9 octaves. The current note name (e.g., A4 at 440 Hz) is displayed automatically. Perfect for tuning instruments, practicing pitch recognition, or ear training exercises.
Volume and speaker balance controls
Adjust volume from 0% to 100% with a single slider. Pan the tone left, right, or keep it centered with the speaker balance control. Useful for testing individual speaker channels or creating spatial audio experiments.
Real-time tone adjustment while playing
Change the frequency, waveform, volume, or balance while the tone is playing. The sound updates instantly without interruption so you can sweep through frequencies and hear the changes in real time.
No download, no account required
This online tone generator runs entirely in your browser. No software installation, no signup, no account needed. Works on desktop and mobile browsers with Web Audio API support.
How to use the online tone generator
A simple step-by-step guide to generating pure tones with this free online frequency generator.
Set your frequency
Use the frequency slider or up/down buttons to choose a frequency in Hz. Or pick a musical note from the note grid below. The current frequency and corresponding note name (e.g., A4) appear at the top.
Choose a waveform
Select one of four waveforms: Sine (clean and pure), Square (buzzy), Sawtooth (harsh), or Triangle (bright). Each produces a different tone character.
Press play
Click the play button to start the tone. The tone plays continuously until you press pause. Adjust the volume to a comfortable level before playing high frequencies.
Adjust volume and balance
Use the volume slider to control loudness and the speaker balance slider to pan the tone between left and right speakers. All adjustments happen in real time while the tone is playing.
Tone generator tips & use cases
Practical ways to use this online frequency generator for audio testing, music, hearing tests, and more.
- 01
Test speakers and headphones
Use this tone generator to check the frequency response of your speakers, subwoofer, or headphones. Play low frequencies (20-200 Hz) to test bass, and high frequencies (8,000-15,000 Hz) to verify treble output.
- 02
Tune musical instruments
Select a reference note like A4 (440 Hz) from the note grid and tune your guitar, piano, violin, or other instrument by ear. A fundamental skill for any musician.
- 03
Test your hearing range
Discover the highest and lowest frequencies you can hear. Healthy adults typically hear from 20 Hz to 17,000 Hz, though the upper limit decreases with age. Start at a low volume and increase carefully.
- 04
Match tinnitus frequency
If you experience pure tone tinnitus (ringing in the ears), sweep through frequencies to find the one closest to your tinnitus pitch. This is called tinnitus frequency matching and can help find masking sounds. Note: this is not a medical device.
- 05
Experiment with acoustic beats
Open this tone generator in two browser tabs. Play 600 Hz in one tab and 602 Hz in the other. The two tones combine to create a rhythmic pulsing beat effect caused by acoustic interference.
- 06
Try binaural beats with headphones
Open two tabs. In one, play 440 Hz panned left. In the other, play 444 Hz panned right. With headphones, your brain perceives a third 4 Hz beat. Some people use binaural beats for meditation, focus, or sleep.
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Protect your hearing
Do not listen to very low frequencies (below 20 Hz) or very high frequencies (above 10,000 Hz) at high volumes for extended periods. Start at low volume and increase gradually.
Sources & References
Authoritative references on audio waveform generation, the Web Audio API, and the acoustics concepts this tone generator demonstrates.
“A sine wave is a geometric waveform that oscillates periodically and is the simplest type of sound wave, consisting of a single frequency with no harmonics.”
Sine wave — the fundamental waveform: Sine wave output is the purest tone this generator produces, containing only the fundamental frequency. It is ideal for hearing tests, speaker testing, and tinnitus frequency matching. en.wikipedia.org/wiki/Sine_wave
“A square wave contains odd harmonics at decreasing amplitude. A sawtooth wave contains both odd and even harmonics. A triangle wave contains odd harmonics at inverse-square amplitude.”
Square, sawtooth, and triangle waveforms: Each waveform produces a distinct harmonic spectrum: square (buzzy, odd harmonics), sawtooth (harsh, all harmonics), and triangle (bright, odd harmonics at lower amplitude). Users switch between them for different testing and sound design needs. en.wikipedia.org/wiki/Waveform
“The OscillatorNode interface represents a periodic waveform, such as a sine or triangle wave. It is an AudioNode that creates a constant tone at a given frequency.”
Web Audio API — OscillatorNode: All tones in this generator are produced via the Web Audio API's OscillatorNode, which natively supports sine, square, sawtooth, and triangle waveforms with precise frequency control from 1 Hz to 20,000 Hz. developer.mozilla.org/en-US/docs/Web/API/OscillatorNode
“The commonly stated range of human hearing is 20 Hz to 20,000 Hz. The upper limit decreases with age, while the lower limit is less affected.”
Human hearing range and frequency perception: The generator covers the full range from 1 Hz to 20,000 Hz. Users can test their personal hearing range by sweeping frequencies, though healthy adult hearing typically spans 20 Hz–17,000 Hz. en.wikipedia.org/wiki/Hearing_range
“A binaural beat is an auditory illusion perceived when two different pure-tone frequencies are presented to each ear separately, typically through headphones.”
Binaural beats — auditory illusion: When two tones with a small frequency difference (e.g., 440 Hz and 444 Hz) are played through separate left/right channels, listeners may perceive a slow rhythmic beat corresponding to the difference frequency. en.wikipedia.org/wiki/Binaural_beats
“A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.”
Acoustic beats — interference phenomenon: Playing two close frequencies (e.g., 600 Hz and 602 Hz) through separate tabs or channels produces a pulsating amplitude effect at the difference frequency, demonstrating acoustic interference. en.wikipedia.org/wiki/Beat_(acoustics)
Frequently Asked Questions
Quick answers about this tool—open a question to read more.