How to use the online tone generator
- Lower your device volume first. Browser output depends on your headphones, speakers and system-level volume. The output gain starts at 10% and is capped at 30% within this tool; that is not a measured sound level.
- Type a frequency between 20 Hz and 20,000 Hz, choose a waveform and press Play tone. The slider is logarithmic so the lower notes have room for precise adjustments. Play requires a click; the page never starts audio automatically.
- Move the frequency slider or choose a preset while the sound plays. Compare the clean sine wave with brighter waves. You can stop immediately, and playback automatically stops after 30 seconds.
- For a quick speaker check, open Frequency sweep, enter start and end frequencies and start the five-second logarithmic sweep. A narrow band that seems unusually quiet or rattly may reflect your room, equipment or level settings, not your hearing.
- To keep a tone, select 1, 5 or 10 seconds and press Download WAV. The file is built locally with a short fade at each end. A WAV download does not turn your speakers on.
What frequency in hertz means
Frequency is the number of complete oscillations per second. A 440 Hz tone repeats 440 times per second; this is the concert A4 reference used by many instruments. Double the frequency to 880 Hz and you move up an octave; halve it to 220 Hz and you move down an octave. This is why the ×2 relationship is useful when comparing a melody in different registers.
For example, a sine wave at 1,000 Hz completes exactly 1,000 cycles per second and has a period of 1 ÷ 1,000 seconds, or 1 millisecond. At 100 Hz, each cycle lasts 10 milliseconds. These examples are arithmetic relationships, not a promise that a particular phone speaker can produce the frequency faithfully.
The four waveforms
| Wave | What you hear | Practical use |
|---|---|---|
| Sine | Pure pitch without extra harmonics | Tuning and reference listening |
| Square | Strong odd harmonics; hollow, sharp sound | Electronic music and timbre comparison |
| Triangle | Odd harmonics that fall rapidly in level | Soft reference tones |
| Sawtooth | Rich in both even and odd harmonics | Bright synth-like sounds |
A sine wave has a single frequency component. The other waves include harmonics at multiples of the chosen fundamental. That means a 1,000 Hz square wave also contains higher-frequency energy. For a basic speaker-frequency check, use the sine wave rather than interpreting a complex waveform as a single test frequency.
Frequency sweep and speaker limits
The sweep changes oscillator frequency exponentially between the entered endpoints over five seconds. A sweep from 100 Hz to 1,600 Hz spans four octaves because 1,600 ÷ 100 = 16 = 2⁴. At the halfway time of 2.5 seconds the frequency is the geometric mean: √(100 × 1,600) = 400 Hz, not 850 Hz. A logarithmic sweep allocates equal time per octave.
Most phones cannot reproduce deep bass at the same level as larger speakers. Your room may also boost or cancel certain frequencies. Quiet high notes do not establish a hearing threshold. Never raise the volume to compensate for a tone that you cannot hear. For individual left/right channel checks try the speaker test; for live sound-level estimates try the decibel meter, with its own calibration limits.
Save WAV tones without an upload
Downloaded files are mono 16-bit PCM sampled at 44,100 Hz. For five seconds, the sample data has 44,100 × 5 × 2 = 441,000 bytes, plus a 44-byte WAV header: 441,044 bytes total. The exported amplitude is intentionally limited and has a 10 ms fade at the beginning and end. A reference file is not a calibrated sound-pressure level, because playback loudness depends on the device. At high frequencies, digital sampling and speaker response can also change the sound.
Listening safely
Keep sessions short and your volume low, especially with earbuds or headphones. The U.S. National Institute on Deafness and Other Communication Disorders explains that louder and longer sound exposure raises hearing-damage risk. This website cannot measure actual decibels reaching your ears. Stop if a sound is uncomfortable. Audio generation uses the browser Web Audio API and does not capture anything from your microphone.
How the browser makes the sound
An OscillatorNode generates the waveform, a GainNode controls output level, and the output reaches your chosen speakers. Your settings can change without reloading. Web browsers generally require a user action before starting sound, so the tool never plays by itself.
Frequently asked questions
Can I generate a 440 Hz sine wave?
Yes. The page starts at 440 Hz with the sine waveform selected. Keep the device volume low and press Play tone to hear the concert A4 reference.
Is the WAV file made on my device?
Yes. A short PCM WAV is generated entirely in your browser. No audio data, setting or uploaded file is sent to a processing server.
Why can I not hear 20 Hz or 20,000 Hz?
Your device may not reproduce those frequencies, the room may cancel them, or your ears may be less sensitive there. The tool is not a calibrated hearing test. Do not raise the volume to force an inaudible tone.
What is the difference between a tone generator and a decibel meter?
A generator sends a chosen waveform to the speakers. A decibel meter estimates sound intensity from a microphone; neither this tool nor its gain setting can tell you the sound pressure reaching your ears.
Can I use the generator for a left/right headset test?
This tool creates a mono signal played through the normal system output. Use the separate speaker test for isolated left and right channel signals.
Last updated: October 19, 2026