Online tone generator
A clean sine wave at the frequency you type. Pick left, right or both and press play.
Press left, right or both to start. Space stops everything.
Sound
Phase
Set an exact frequency
Type any frequency from 20 to 20000 Hz in the exact field, decimals included (for example 60.45), and press Enter. The up and down arrow keys in the field step the value by 1 Hz, or by 10 Hz with Shift. The slider covers the same range on a logarithmic scale.
What it is good for
A pure tone helps to find a part that rattles at one pitch, to check how low a speaker really goes, to tune an instrument by ear against a reference, or to compare the two channels of a stereo system. 440 Hz is the usual concert A.
Limits
The tone is a plain sine wave. Tones below 35 Hz are cut on purpose to protect small speakers, and the output level is limited. This is not a measuring instrument: your system, the speaker and the room all shape what you hear.
Questions
What do Tone, Noise and Sweep do?
Tone is a pure sine wave at the frequency you choose, handy for finding a part that rattles at one pitch. Noise is a steady hiss in five colours. Sweep glides from 20 Hz to 20 kHz in about twelve seconds, so you can hear where a speaker starts to fade, rattle or distort.
Why can't I hear the lowest or highest tones?
Both your hearing and your speakers have limits. Many people hear from about 20 Hz to 20 kHz when they are young, and the top end fades with age. Small laptop and phone speakers often play very little below roughly 100 Hz.
This page also cuts tones under 35 Hz on purpose, because they only make small speakers move without making sound. A sweep that seems to start late or end early is therefore normal.
Is it safe for my speakers and my ears?
The page starts at a low volume, limits its maximum level, fades sounds in and out and filters out the deepest bass, which all helps. It cannot make a damaged or very small speaker safe, though.
Keep the volume moderate, avoid long loud tones in the lowest and highest ranges, and stop at the first sign of distortion: Space stops everything at once. Loud sound can also harm your hearing. You use the page at your own risk.
How accurate is a browser speaker test?
It is good enough to find a dead channel, swapped sides, a rattle or obvious distortion. It is not a measurement. Your system may apply sound enhancements, the speaker and the room shape what you hear, and without a calibrated microphone there are no real numbers. For acoustic measurements you need proper equipment.