A simple tone generator: enter a frequency and play a pure sine wave. Use it to tune an instrument (440 Hz is standard 'A'), test the range of speakers or headphones, or check your hearing. Want the current time alongside? Use the frequency clock.
Guides about Tone Generator
432 Hz vs 440 Hz
432 Hz vs 440 Hz: What the Tuning Debate Really Means
A balanced look at the 432 Hz versus 440 Hz tuning debate, explaining what concert pitch is, where the argument comes from, and why superiority claims remain unproven.
432 Hz vs 440 Hz
The History of A440: How We Agreed on Concert Pitch
The story of how musicians came to agree on 440 Hz as concert pitch, why tuning varied wildly for centuries, and the myths that have grown around the standard.
Tone generator uses
How to Tune an Instrument With a Reference Tone
A step-by-step guide to tuning any instrument by ear with a pure reference tone, from choosing the right frequency to matching pitch and avoiding common mistakes.
Testing speakers & hearing
Online Hearing Range Test: Find Your High-Frequency Limit
How to run an informal hearing range test with a tone generator, find your high-frequency ceiling, understand what it means, and why it is no substitute for a real test.
Frequency & hertz explained
Sine vs Square Waves: Why Waveform Shape Changes Sound
How the shape of a sound wave changes what you hear, comparing pure sine tones with buzzy square and sawtooth waves, and why timbre matters as much as frequency.
Testing speakers & hearing
How to Test Your Speakers' Frequency Response With Tones
A hands-on guide to testing your speakers or headphones with pure tones, running a frequency sweep to find the limits, spotting buzzes and dead spots, and staying safe.
More frequencyclock pages
Frequently asked questions
What can I use it for?
Tuning instruments, testing speaker/headphone frequency response, informal hearing checks, and sound experiments.
Is it a pure tone?
Yes — it produces a single sine-wave frequency with no overtones.