Tone generator
Pick a frequency and a wave shape, then press play. Change them while it plays.
Start with a low volume. Loud or very high tones can hurt your ears and bother pets. On iPhone, switch off silent mode to hear the tone.
What you can use it for
Speaker and headphone checks
Hear rattles, buzzing or missing notes at any frequency.
Tuning instruments
440 Hz is the A that most instruments tune to.
Hearing range
Find the highest tone you can still hear.
Science and school projects
See and hear how frequency and wave shape change a sound.
Questions people ask
What is the difference between the wave shapes?
Sine is the purest and softest. Square and sawtooth sound harsher and buzzier because they contain many extra tones. Triangle is in between.
What frequency removes water from a phone speaker?
A low tone around 165 Hz works well. Use the Water eject preset, or the main Water Ejector tool with timer and modes.
Why can I not hear very high frequencies?
Hearing range gets smaller with age, and small speakers often cannot play very high or very low tones.
Does it work offline?
Yes. After your first visit the page keeps working without internet.