Online Tone Generator
Pick a frequency from 20 Hz to 20,000 Hz and press Play. Choose sine, square, sawtooth or triangle, pan it left or right, or sweep across a range. Runs in your browser — no download.
frequency
440 Hz
Start quiet and turn up slowly, especially with headphones. Very low and very high tones can be louder than they seem, and some you may not hear at all while they still reach your ears.
musical notes
test tones
sweep (log)
A log sweep spends equal time on each octave, so 20–200 Hz takes as long as 2–20 kHz.
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One tone, a lot of uses
A steady tone at a known frequency is the simplest audio test there is. It tells you what a speaker can play, where a rattle is coming from, whether an instrument is in tune, and how high you can still hear.
- 01
Test speakers
Sweep 20 Hz to 200 Hz to find where the bass fades out, and listen for rattles and buzzing.
- 02
Tune by ear
Play A4 at 440 Hz or middle C and match your instrument until the beating stops.
- 03
Check left and right
Move the balance fully left, then right, to confirm each channel plays.
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Common questions
How do I play a specific frequency?
Type the number in the “exact Hz” box, or drag the slider, then press Play tone. Use ±1 and ±10 for fine steps, ×2 and ÷2 to jump an octave. The address bar updates with ?f= and ?w=, so you can share or bookmark that exact tone.
What is the difference between sine, square, sawtooth and triangle waves?
A sine wave is a single pure frequency. Triangle adds a few soft odd harmonics. Square adds strong odd harmonics and sounds hollow and buzzy. Sawtooth has every harmonic and sounds bright and harsh. For testing speakers or hearing, use sine.
What frequency is A4, and middle C?
In standard tuning A4 is 440 Hz and middle C (C4) is about 261.63 Hz. Each octave doubles the frequency, so A5 is 880 Hz and A3 is 220 Hz. The note buttons set these exactly.
Why can I not hear very low or very high tones?
Small speakers, including phone and most laptop speakers, cannot play deep bass, so 20–80 Hz often comes out faint or silent. At the top end, many people cannot hear much above 15–17 kHz, and some headphones cannot play it. Try headphones for low tones, and see our hearing test for high ones.
Is it safe to use a tone generator?
Yes, at sensible volume. Start low, raise it slowly and keep sessions short with headphones. Do not turn the volume up just because a very low or very high tone seems quiet — it can still be loud for your ears or strain your speakers.
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Clear sound, in every language
OmniTalk speaks your translations out loud, in real time, across 60+ languages — so clear audio matters. Its Split Ears mode even sends each person’s language to a different earbud, the same left/right separation as the balance control here.
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