This frequency generator plays any tone from 1 Hz to 20,000 Hz directly in your browser. Slide to a frequency or type an exact number, pick a waveform, and press play. The tone changes live while it plays, which makes sweeping through a range effortless. No app, no signup, and it works on phones, tablets, and computers.
A tone generator sounds like a niche tool until you need one, and then it solves a surprising range of problems. Here are the jobs people actually use it for.
What You Can Do with a Frequency Generator
- Eject water from a speaker. Low tones around 165 Hz make the speaker membrane move forcefully enough to push water out, the same principle as the Apple Watch water eject feature. The preset is there for emergencies, though for a guided multi-stage process our dedicated water eject tool does the work for you.
- Test speakers and headphones. Sweep from low to high and listen for rattles, dropouts, or distortion at specific frequencies. A speaker that buzzes only around certain bass tones has a loose component or debris; our speaker cleaner handles the debris case. For a guided version of these checks, use the headphone test.
- Check the edges of your hearing. Human hearing tops out near 20 kHz in childhood and drops with age; many adults hear little above 14 to 16 kHz. Sliding upward until the tone disappears is a quick, informal check. Keep the volume moderate, this is a curiosity check rather than a medical test. For a guided version with a proper tone ladder, take the hearing frequency test.
- Tune an instrument. The 440 Hz preset is concert pitch A4, and the note display shows the nearest musical note for any frequency you dial in.
- Find resonances and rattles in a room. Play sustained bass tones and objects that buzz along reveal themselves: loose grills, shelf items, car door panels.
Choosing a Waveform
The four waveforms sound different because they carry different harmonics. Sine is the pure tone with no harmonics, the right choice for hearing checks, water ejection, and clean reference tones. Square and sawtooth stack strong harmonics on top of the base frequency, which makes them sound buzzy and aggressive; they are useful for testing how equipment handles harmonic-rich content, and they reveal speaker distortion faster. Triangle sits between: a softer character with gentle harmonics. When in doubt, stay on sine.
Using Frequencies Safely
Two ranges deserve respect. Above roughly 8 kHz, tones can be piercing at volume, and with earphones sitting directly in your ears, loud high-frequency tones are genuinely unpleasant and potentially harmful; lower the volume before exploring the top of the range, and the tool reminds you when you enter it. Below 40 Hz, most phone speakers produce almost nothing audible, so the temptation is to crank the volume; resist it with headphones on, because the driver is still working hard even when you hear little. At normal volumes, tones across the range are the same ordinary audio your device plays all day.
Related Tools
This generator is the free-form version of several of our dedicated tools. For checking left and right channels separately, use the sound test; for a guided dust cleaning sweep, the speaker cleaner; for checking your voice input, the microphone test. For a guided tour of the low end, the bass test plays preset tones and finds your device’s bass floor.
FAQ
What frequency should I use to get water out of my speaker?
Tones between roughly 160 and 440 Hz work best, and 165 Hz is the value Apple uses for the Apple Watch water eject feature. Set volume to maximum, point the speaker down, and play for 10 to 15 seconds at a time. For a guided multi-stage version, use our dedicated water eject tool.
What is 1 kHz used for?
1000 Hz is the standard reference tone in audio work. Equipment sensitivity, volume calibration, and level matching are conventionally done at 1 kHz because it sits in the middle of the hearing range where ears and equipment are most consistent.
Why can't I hear anything above 15 kHz?
That is normal adult hearing. Sensitivity to high frequencies declines naturally with age, starting from the late teens. Most adults hear little above 14 to 16 kHz, and phone speakers themselves also weaken near the top of the range, so the limit you find mixes both factors.
Is playing a constant tone bad for my speaker?
No, at normal volumes a sustained tone is ordinary audio. The one situation to avoid is playing very low frequencies at maximum volume through tiny speakers for long stretches, since the driver works hard producing sound you barely hear. Short tests are completely safe.
What is the difference between sine and square waves?
A sine wave contains only the base frequency, so it sounds pure and smooth. A square wave adds strong odd harmonics on top, which makes it sound buzzy and harsh at the same pitch. Sine is right for tests and reference tones; square is useful for stress-testing equipment with harmonic-rich content.