What frequency is A4?

A4 (concert pitch) is 440 Hz. This is the standard tuning reference used by most musicians and orchestras worldwide.

What is the difference between sine, square, sawtooth, and triangle waves?

Sine waves produce the purest tone with no harmonics. Square waves have odd harmonics and sound buzzy. Sawtooth waves contain all harmonics and sound bright. Triangle waves have odd harmonics but are softer than square waves.

Can I use this for hearing tests?

Yes, this tone generator can be used to test your hearing range. Most adults can hear from about 20 Hz to 20,000 Hz, though the upper limit decreases with age.

Online Tone Generator

Frequency 440 Hz

20 Hz20,000 Hz

Volume 50%

Waveform

Musical Notes (Equal Temperament)

Common Frequencies

How to Use

Set the desired frequency using the slider or click a preset note.

Choose a waveform type: Sine (pure), Square, Sawtooth, or Triangle.

Adjust the volume, then click the play button to start the tone.

Features

Full Frequency Range Generate tones from 20 Hz to 20,000 Hz — the full range of human hearing.

4 Waveform Types Sine, square, sawtooth, and triangle waves for different tonal qualities.

Musical Note Presets Quickly jump to any note on the equal temperament scale.

Real-time Visualizer See the waveform rendered live as the tone plays.

100% Browser-Based Powered by the Web Audio API. No plugins, no downloads, no sign-up.

Adjustable Volume Fine-tune the volume from 0% to 100% with a smooth slider.

Use Cases

Musicians use this tool for instrument tuning — generate A4 at 440 Hz to tune guitars, violins, or other instruments by ear.

Audio engineers use tone generators for speaker and amplifier testing. Send a 1 kHz sine wave to check frequency response and distortion.

Test your hearing range by sweeping from 20 Hz upwards. As you age, high-frequency hearing declines.

Some people find specific frequencies (like 432 Hz or 528 Hz) useful for meditation or focus.

Teachers and students can use this to demonstrate the physics of sound waves.

FAQ

What is a tone generator used for?

Tone generators are used for instrument tuning, audio equipment testing, hearing tests, sound therapy, and educational demonstrations of acoustics and waveform physics.

What frequency is concert pitch A4?

Concert pitch A4 is 440 Hz. This is the international standard for tuning reference, adopted by the International Organization for Standardization (ISO 16) in 1955.

What is the difference between sine and square waves?

A sine wave produces a pure, smooth tone with no harmonics. A square wave contains the fundamental frequency plus all odd harmonics, creating a buzzy sound similar to clarinets or retro game audio.

Can I use this to test my speakers?

Yes! Start with a 1 kHz sine wave at moderate volume, then sweep through different frequencies. Be cautious with very high volumes at extreme frequencies as this can damage speakers.

Is this safe to use?

Yes, but use at reasonable volume levels. Prolonged exposure to very loud tones can cause hearing damage. Always start at low volume and increase gradually.

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