Pitch reference
Use 440 Hz as a reference when working with standard A4 concert pitch.
REFERENCE TONE
440 Hz Tone
Play a clean 440 Hz reference tone directly in your browser. The frequency is preselected so you can start testing immediately.
AUDIO FREQUENCY
440 Hz
Ready
WaveformSmooth and pure
sine20 Hz – 20 kHz
Hz
20 Hz1 kHz10 kHz20 kHz
Quick frequenciesλ ∝ 1 / f
Frequency440 Hz
×
Visual wavelength180.0 px
1.00× longer wavelength than 440 Hz
Start audio only when you press play. Keep your device volume low before testing.
ABOUT 440 HZ
Why is 440 Hz important?
440 Hz is widely used as the reference frequency for A4, the A above middle C. It provides a common reference when tuning instruments and discussing musical pitch.
A pure 440 Hz sine tone is also useful for basic audio testing because it contains one primary frequency rather than the collection of frequencies found in complex sounds such as music.
COMMON USES
What can you use a 440 Hz tone for?
Audio testing
Use a steady reference tone when checking whether an audio system produces sound.
Instrument tuning
A 440 Hz reference can be used as a starting pitch when tuning instruments by ear.
FAQ
Frequently asked questions
What is a 440 Hz tone?
A 440 Hz tone is a sound wave oscillating at 440 cycles per second. 440 Hz is commonly used as the reference pitch for A above middle C, often called A4.
Can I play a 440 Hz tone online?
Yes. This page generates a 440 Hz tone directly in your browser using the Web Audio API. No audio file needs to be downloaded.
What is 440 Hz used for?
440 Hz is commonly used as a reference frequency when tuning musical instruments and discussing standard concert pitch.
What waveform does the generator use?
The generator starts with a sine waveform because it produces a simple, clean single-frequency tone. Other waveform options are also available.
Should I use high volume for a 440 Hz test tone?
No. Start with your device volume low and increase it only as needed. Continuous tones do not need to be played at a high level.