What frequency should I use to tune my instrument?

The most common reference is A4 = 440 Hz, the international standard pitch used by orchestras worldwide. If you need to tune a guitar, set the tone generator to E2 (82 Hz) for the low E string, A2 (110 Hz), D3 (147 Hz), G3 (196 Hz), B3 (247 Hz), or E4 (330 Hz) for the high E string.

What is the difference between sine, square, sawtooth, and triangle waveforms?

A sine wave is the purest tone — a single frequency with no harmonics. A square wave sounds buzzy and contains only odd harmonics. A sawtooth wave is bright and contains all harmonics (both odd and even). A triangle wave sounds softer than a square wave and contains only odd harmonics but with lower amplitudes. For reference tones and tuning, sine is almost always the best choice.

Can I use a tone generator for a hearing test?

Yes — a simple hearing test involves playing tones from about 250 Hz up to 8,000 Hz and noting the quietest level at which you can still hear each frequency. Normal adult hearing covers roughly 20 Hz to 20,000 Hz, though sensitivity decreases with age at higher frequencies. For a proper audiological hearing test, consult a licensed audiologist with calibrated equipment.

What is 432 Hz vs 440 Hz tuning?

440 Hz is the internationally standardized concert pitch (ISO 16) used by most professional musicians and orchestras since 1955. 432 Hz is an alternative tuning popular in some online communities, claimed to sound 'warmer' or 'more natural', though there is no scientific evidence for any advantage. To explore both, simply set this tone generator to 432 Hz or 440 Hz and compare.

Is this tone generator safe to use at high volumes?

Listening to loud tones — especially at very low or very high frequencies — can cause hearing fatigue or damage. Always start at a low volume and increase gradually. Frequencies below about 60 Hz can feel uncomfortable at high volumes, and frequencies above 10,000 Hz are tiring for long exposures. Never use a tone generator at maximum volume with headphones.

Free Online Tone Generator

Generate a pure audio tone at any frequency from 20 Hz to 20 kHz. Choose your waveform, adjust the volume, and play — no download or sign-up required.

Note:A4

Frequency

20 Hz1001 kHz10 kHz20 kHz

Musical Notes

Common Frequencies

Waveform

Volume — 50%

⚠ Start at low volume. Very loud tones can damage your hearing.

How to Use the Tone Generator

Set your target frequency using the Hz input or the slider.
Click a musical note preset (A4, C4, etc.) for quick access to common reference tones.
Choose a waveform — Sine for a pure tone, Square or Sawtooth for harmonics.
Adjust the volume slider before pressing Play.
Press Play Tone — the generator starts immediately. Press Stop to end.

Frequency Reference Table

Common reference frequencies for musical instruments, hearing tests, and audio calibration.

Note / Range	Frequency	Common Use
A0	27.5 Hz	Lowest key on a piano
C1	32.7 Hz	Lowest standard bass guitar note
E2	82.4 Hz	Low E string — guitar
A2	110 Hz	A string — guitar
D3	147 Hz	D string — guitar
G3	196 Hz	G string — guitar
A3	220 Hz	Standard viola A-string
A4	440 Hz	Concert pitch reference (standard tuning)
C5	523 Hz	Middle C one octave up
A5	880 Hz	A4 one octave higher
4 kHz	4,000 Hz	Most sensitive range of human hearing
8 kHz	8,000 Hz	Upper speech range, hearing test checkpoint

What Is a Tone Generator Used For?

Instrument tuning reference

Play a reference note like A4 (440 Hz) and tune your string, wind, or keyboard instrument to match it by ear.

Speaker & headphone testing

Sweep through different frequencies to identify resonances, distortion, or dead spots in your audio equipment.

Hearing test

Play tones from 250 Hz to 8 kHz at low volume to check which frequencies you can still hear clearly.

Audio equipment calibration

Use a 1 kHz sine tone as a standard reference signal for adjusting levels and gain staging in your recording chain.

Sleep & tinnitus masking

Some users find low-frequency tones or specific noise profiles helpful for masking tinnitus. Try frequencies between 2–5 kHz at very low volume.

Physics & acoustics education

Demonstrate waveforms, harmonics, resonance, and standing waves in classroom or home-lab settings.

Frequently Asked Questions

: A tone generator produces a continuous audio signal at a chosen frequency. They're used for hearing tests, speaker and headphone testing, musical tuning references, audio equipment calibration, and acoustics experiments.
: The standard reference is A4 = 440 Hz. For guitar, common reference tones are E2 (82 Hz), A2 (110 Hz), D3 (147 Hz), G3 (196 Hz), B3 (247 Hz), and E4 (330 Hz).
: A sine wave is the purest tone — no harmonics. A square wave is buzzy with odd harmonics. Sawtooth is bright with all harmonics. Triangle is soft with only weak odd harmonics. For tuning and hearing tests, use sine.
: Yes — play tones from 250 Hz to 8,000 Hz and note which you can hear clearly. Normal adult hearing spans roughly 20 Hz – 20,000 Hz. For medical audiological testing, always see a licensed audiologist.
: 440 Hz is the international concert pitch standard (ISO 16) used worldwide since 1955. 432 Hz is a popular alternative sometimes called 'Verdi tuning'. There is no scientific evidence for audio quality differences — you can compare both freely with this generator.
: Always start at low volume and increase gradually. Loud tones — especially below 60 Hz or above 10 kHz — can cause hearing fatigue. Never use maximum volume with headphones.