---
title: "Online Tone Generator - 20 Hz to 20 kHz"
description: "Online tone generator for sine, square, triangle, and sawtooth signals from 20 Hz to 20 kHz. Play or download a WAV locally in your browser."
url: https://candoya.com/tools/tone-generator/
locale: en
type: browser-tool
---

# Free Online Tone Generator

Category: [Social & Creator](https://candoya.com/tools/social/)

## What is an online tone generator?

An online tone generator creates a steady audio signal at the frequency and waveform you choose. Set any value from 20 Hz to 20 kHz, select sine, square, triangle, or sawtooth, then listen or save a short WAV. The signal is synthesized locally by your browser after you press Play.

This tool uses the Web Audio API for live playback and offline WAV rendering. A short gain fade at the start and end reduces clicks, while the logarithmic slider gives low and high frequencies useful space. No microphone, audio upload, account, or plug-in is required.

**Hearing safety matters:** start with low browser and device volume. The on-screen percentage controls digital gain, not sound pressure at your ear. Stop immediately if a tone feels uncomfortable.

## How to use it

1. **Choose a frequency** - Type an exact value from 20 to 20,000 Hz, move the logarithmic slider, or select a common preset.
2. **Select the waveform** - Use sine for a single fundamental or choose square, triangle, or sawtooth when you need audible harmonics.
3. **Set a low output level** - Keep the tool and your device volume low before you start, especially with headphones.
4. **Play or save** - Press Play tone for continuous sound, then Stop tone when finished, or choose a duration and download a mono 48 kHz WAV.

## Who it's for

- **Musicians and producers** can use 440 Hz or another exact pitch as a tuning and arrangement reference.
- **Audio technicians** can check whether a speaker path reproduces common bass, midrange, and treble test frequencies.
- **Students** can compare the sound and shape of sine, square, triangle, and sawtooth waves.
- **Developers** can save a short WAV fixture for media controls, demos, or local application testing.

## Expert note

Only a sine oscillator contains one ideal frequency. Square, triangle, and sawtooth waves add harmonics, so they can sound much brighter and may stress small speakers more at the same digital level. A high-frequency setting that you cannot hear can still be active, so never raise the level just to force an audible result.

## Frequently asked questions

### Is this online tone generator free?

Yes. You can play tones and download short WAV files without an account, payment, or usage limit. The controls cover 20 Hz to 20 kHz, four standard oscillator waveforms, common frequency presets, output level, and WAV durations from one to ten seconds.

### Does the tone generator upload or record audio?

No. The tool does not request microphone access, record sound, or upload audio. Live tones and downloadable WAV samples are synthesized on your device through browser audio APIs. Ordinary site resources or analytics may still make page requests, so this privacy claim applies specifically to tone generation.

### What frequency range can I generate?

You can generate values from 20 Hz to 20,000 Hz, including decimals. This spans the conventional human-audible range, but actual audibility depends on age, hearing, speakers, headphones, device filters, and room conditions. Inaudible does not necessarily mean the signal is absent.

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

A sine wave has one fundamental frequency. Square waves add strong odd harmonics, triangle waves add softer odd harmonics, and sawtooth waves include both even and odd harmonics. Those added frequencies make non-sine shapes sound brighter even when the frequency control shows the same fundamental.

### Why do I have to press Play before sound starts?

Modern browsers usually block audio that starts without a user action. Pressing Play lets the page create or resume its audio context. If the status says Playing but you hear nothing, check the device output, keep the level low, and confirm that the selected frequency is within your equipment's range.

### Can I use this as a hearing test?

No. This is a signal generator, not a calibrated audiometer or medical hearing test. Browser gain, device volume, headphone sensitivity, frequency response, and background noise are uncontrolled. Do not use a result to diagnose hearing loss, and stop immediately if any sound is painful or uncomfortable.

### How is the downloadable WAV made?

The browser renders the selected oscillator into a mono 48 kHz audio buffer, applies short fades to reduce boundary clicks, and encodes 16-bit PCM WAV data locally. The saved file contains the chosen waveform, frequency, level, and duration, with no server conversion.

## Related tools

- [Metronome](https://candoya.com/tools/metronome/)
- [Text to Speech](https://candoya.com/tools/text-to-speech/)
- [Audio Waveform Image](https://candoya.com/tools/audio-waveform-image/)
- [Audio Volume Changer](https://candoya.com/tools/volume-changer/)
- [Audio Normalizer](https://candoya.com/tools/audio-normalizer/)

---

*Markdown edition of <https://candoya.com/tools/tone-generator/>, published for AI agents and other automated readers. Index of key pages: <https://candoya.com/llms.txt>.*