Online Tone Generator — Pure Tones, Binaural Beats & Note Picker
Generate pure tones at any frequency using sine, square, sawtooth or triangle waveforms. The Note Picker tab shows a piano keyboard — click any key to instantly set its frequency and play the tone. Furthermore, the Binaural Beat mode plays two slightly different frequencies in each ear — useful for focus, relaxation and sleep. One-click presets include 40 Hz Gamma, 10 Hz Alpha, 4 Hz Theta and 1 Hz Delta. Download any tone as a 10-second WAV file.
How to use the Online Tone Generator
Enter a frequency or use the Note Picker
Type any frequency in Hz in the Single Tone tab (20–20,000 Hz). Furthermore, the Note Picker tab shows a three-octave piano keyboard — click any key to set its exact frequency automatically and begin playing. The stat strip shows the closest musical note, octave, cents offset and wavelength.
Select a waveform
Choose from sine (pure, smooth), square (buzzy, rich in harmonics), sawtooth (bright, harsh) or triangle (warm, gentle). Furthermore, each waveform has a distinct timbre — sine is the purest tone with no harmonics; square adds strong odd harmonics; sawtooth adds all harmonics; triangle has softer, quieter harmonics.
Adjust volume and press Play
Set the volume slider to a comfortable level — start low, especially with headphones. Furthermore, click Play Tone or press Enter to start the tone. The tone plays continuously until you press Stop. The frequency stat strip updates instantly when you change the frequency while playing.
Try the Binaural Beats mode
Click the Binaural Beats tab and select a preset — 40 Hz Gamma for focus, 10 Hz Alpha for relaxation, 4 Hz Theta for meditation or 1 Hz Delta for sleep. Furthermore, put on headphones (essential for binaural beats) and press Play Binaural Tone. The left and right ear hear slightly different frequencies, creating a perceived beat at the difference.
Download a WAV file
Click Download WAV to render a 10-second WAV file of the current tone at the current frequency and waveform. Furthermore, this file is compatible with every audio software and can be used as a reference tone, test signal or sound design starting point. The filename includes the frequency for easy identification.
The four waveforms and their uses
Each waveform has a distinct harmonic content that determines its timbre. Furthermore, the same frequency played through different waveforms sounds completely different — this is the foundation of synthesis and sound design.
| Waveform | Harmonic content | Sound character | Common uses |
|---|---|---|---|
| Sine | Fundamental only (no harmonics) | Pure, smooth, clinical | Tuning reference, hearing tests, tinnitus matching, audio testing |
| Square | Odd harmonics (3rd, 5th, 7th…) | Buzzy, hollow, retro | Chiptune/8-bit sounds, clarinets, vintage synths |
| Sawtooth | All harmonics (odd and even) | Bright, harsh, aggressive | Strings, brass simulation, lead synth sounds |
| Triangle | Odd harmonics (quieter than square) | Soft, warm, flute-like | Flutes, soft leads, sub bass augmentation |
Musical note frequencies
The standard tuning reference is A4 = 440 Hz — the note A in the fourth octave. Furthermore, all other notes derive from this reference using the equal temperament formula: each semitone is a ratio of 2 to the power of 1/12 (approximately 1.05946). Moreover, the Note Picker tab handles this calculation automatically — click a key and the correct frequency appears instantly.
How tone frequency relates to musical notes
The equal temperament system places all 12 semitones of the octave at equal frequency ratios. Furthermore, doubling a frequency raises the pitch by exactly one octave. This means A4 = 440 Hz, A5 = 880 Hz and A3 = 220 Hz.
Middle C = MIDI 60 = 261.63 Hz
C5 = MIDI 72 = 523.25 Hz
Wavelength = 343 m/s ÷ frequency (speed of sound in air at 20°C)
How binaural beats work
Binaural beats require headphones. Furthermore, the left ear hears one frequency and the right ear hears a slightly different frequency. The brain perceives the difference between the two frequencies as a slow pulsing beat. Moreover, at 10 Hz difference (Alpha range), some users report increased relaxation. At 40 Hz (Gamma range), users report heightened focus. These effects are studied but not conclusively proven in clinical research.
Worked example: setting up a binaural Alpha session
A user wants to use 10 Hz Alpha binaural beats for a 20-minute relaxation session. Here is the setup:
| Setting | Value | Note |
|---|---|---|
| Left ear frequency | 200 Hz | A carrier in the comfortable hearing range |
| Right ear frequency | 210 Hz | Carrier + 10 Hz beat frequency |
| Perceived beat | 10 Hz (Alpha) | The difference the brain perceives |
| Waveform | Sine (both ears) | Purest tone for binaural use |
| Volume | 20–30% | Just audible — keep it low |
What is a tone generator?
A tone generator produces sound at a precisely controlled frequency and waveform. Furthermore, it uses electronic oscillation — in this case the Web Audio API — to create tones from 20 Hz (the lower limit of human hearing) to 20,000 Hz (the upper limit for most adults). A pure sine wave contains only the fundamental frequency with no harmonics.
Tone generators have been core instruments in audio engineering for over a century. Furthermore, they test microphones, speakers, amplifiers and hearing. Sound designers use them as synthesis starting points. Music teachers use reference tones to help students tune instruments. Moreover, the tool also serves occupational health — audiologists use calibrated tones to test hearing thresholds across frequencies.
Tinnitus matching
People with tinnitus often use tone generators to identify the frequency of their ringing. Furthermore, by matching the generator frequency to the perceived ringing, they can identify the precise pitch. This information helps audiologists design tinnitus masking therapies. Moreover, knowing the tinnitus frequency also helps users find sound masking content tuned to that specific range.
Audio equipment testing
Audio engineers use tone generators to test equipment frequency response. Furthermore, sweeping from 20 Hz to 20,000 Hz through speakers reveals resonances, roll-offs and distortion points. Moreover, the downloadable WAV files can be played through any audio system to test frequency response without requiring specialised equipment.
Why tone generators matter for musicians and engineers
Every piece of audio equipment handles different frequencies differently. Furthermore, a subwoofer designed to reproduce 20–80 Hz will sound very different from a tweeter designed for 2,000–20,000 Hz. A tone generator lets you probe these differences directly. Moreover, testing monitors, headphones and room acoustics with sine sweeps reveals the true frequency response of your listening environment.
The Note Picker keyboard bridges music theory and signal analysis. Furthermore, when you need to know the exact frequency of middle C for a software synthesiser calibration, clicking the C4 key gives you 261.63 Hz instantly. Moreover, the cents display shows how far any custom frequency deviates from the nearest equal temperament note — valuable for just intonation experiments and microtonal music.
Binaural beats in productivity and wellness
Binaural beats have gained significant attention in wellness and productivity communities. Furthermore, while the clinical evidence remains mixed, millions of users report benefits for focus, relaxation and sleep onset when using binaural frequencies consistently. Moreover, the four presets — Gamma (40 Hz), Alpha (10 Hz), Theta (4 Hz) and Delta (1 Hz) — cover the four main brainwave ranges studied in this field.
Frequently asked questions
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