White noise
Press play for true white noise: every frequency from 20 Hz to 20 kHz at equal power, generated in your browser so it never loops audibly.
- Spectrum
- Flat: 0 dB per octave (equal power per hertz)
- Good for
- Masking speech and sudden noises
- Tinnitus relief at low volume
- A familiar "shhh" for babies
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What is white noise?
White noise is a random signal with the same power at every frequency. The name borrows from white light, which contains all visible colours. On the dial above, its trace rises steadily to the right: each octave spans twice as many frequencies as the one below it, so a flat-per-hertz signal packs twice the energy into each higher octave.
That is why white noise sounds bright and hissy, like radio static or a TV between channels, even though no single pitch is louder than any other.
Why white noise helps you sleep or focus
Noise does not make a room quieter. It raises the background level so that sudden sounds (a door, a car, a partner snoring) stand out less. Your brain reacts to change more than to loudness, and a steady wideband sound shrinks the change.
A 2021 systematic review in Sleep Medicine Reviews (Riedy et al.) found the evidence for noise as a sleep aid is still low quality, so treat it as a comfort tool, not a treatment. Many people prefer the softer pink or brown noise for all-night use.
How loud should white noise be?
Keep it at the level of a quiet shower or softer, roughly 50 dB at your ear. The World Health Organization advises keeping night-time noise low, and the American Academy of Pediatrics recommends machines for infants stay under 50 dB and well away from the cot.
Compare white, pink and brown noise · All noise colours explained
Questions
Is this white noise free?
Yes. It is generated in your browser with the Web Audio API, so there is nothing to download, no account and no ads.
Does the sound loop?
The noise is synthesised as a long random buffer and shaped so the end joins the start with no click. Random noise has no pattern for your ear to catch, so you will not hear a loop point.
Is white noise bad for you?
At moderate volume it is considered safe for adults. Very loud sound for hours can harm hearing, so keep it quieter than normal conversation and use the timer if you fall asleep with it.
White, pink or brown: which is best for sleep?
There is no single winner. White masks best across the board but can feel harsh; pink and brown put more energy into the low end and most people find them calmer. Try each for a night.
Will it keep playing with my screen off?
On most phones yes, as long as the browser tab stays open. iPhone Safari may pause audio if you lock the phone with the tab in the background; keep the tab in front, or use the media controls on the lock screen.