White Noise & Rain Sounds

Q: Is white noise safe for babies?

Volume, distance and duration matter. A study published in Pediatrics found that sleep machines close to the crib can be too loud. So: quiet, far from the crib, with a timer. When in doubt, ask your pediatrician.

Noise to focus, relax or fall asleep – generated right in your browser, no download and no recordings. Pick a sound, set the volume, add a timer if you like.

How it is calculated

This generator creates white, pink and brown noise as well as rain sounds with optional thunder. Every sound is computed in your browser when you press “Play” – there are no audio files, no recordings and no ad breaks like in videos.

How it works

Pick a preset (White, Pink, Brown, Rain, Thunderstorm) or set the sliders under “Mix” yourself – all sounds can be combined.
Use the master volume and your device volume to reach a pleasant, rather quiet level.
Optionally set a timer: towards the end the noise fades out gently over up to 60 seconds and then stops.

White, pink, brown – what’s the difference?

White noise has equal power per hertz across all frequencies. Because higher octaves span many more hertz than low ones, it sounds bright and hissy – like an untuned radio.
Pink noise drops by 3 dB per octave, so every octave carries the same energy. To the ear it sounds more balanced and softer, like steady rain or a waterfall. It is generated here with Paul Kellet’s well-known filter.
Brown noise (named after Robert Brown and Brownian motion, not the colour) falls by 6 dB per octave. It sounds deep and muffled, like distant surf or an airplane cabin. It is made by summing up (integrating) white noise.
Rain is filtered noise as a steady patter plus hundreds of random, short “drops” per second. Thunder is heavily low-passed brown noise with slow swells.

Endless without an audible seam

Each sound is computed once as a loop of 12 to 40 seconds and then repeated endlessly. To hide the join, the end of the loop is cross-faded into its beginning over half a second. The slopes (−3 dB and −6 dB per octave) are verified by automated frequency analysis.

A note on babies and volume

Noise is often used to help babies fall asleep. A study in Pediatrics, the journal of the American Academy of Pediatrics (Hugh et al., 2014), measured that commercial infant sleep machines at high settings and close to the crib can reach levels considered too loud for infants. The authors advise, in essence: place the device as far from the crib as possible, keep the volume as low as possible and don’t run it all night – a timer helps. So never put your phone or speaker right next to the baby’s head.

Honest limits

Noise is not a medical treatment. Whether it helps you sleep or focus varies from person to person; for sleep problems or ringing in the ears (tinnitus), see a doctor.
The rain is synthetic: it sounds like rain but is not a recording of a real storm.
On phones, some browsers stop the sound when the screen turns off or the tab goes to the background. Keep the screen on or the page in the foreground.
Actual loudness depends on your device and speakers; the percentages are not decibels.

Privacy

The sound is computed entirely in your browser with the Web Audio API. Nothing is downloaded, uploaded or stored – not even your slider settings.

Related: the sleep calculator finds the best wake-up time based on sleep cycles, and the Pomodoro timer splits focused work into blocks.

Frequently asked questions

Is white noise good for sleep?

Many people find a steady noise pleasant because it masks sudden sounds like traffic or neighbours. There is no guarantee of better sleep – try it at a low volume and use the timer so it doesn’t run all night.

What is the difference between white, pink and brown noise?

White noise has equal power at all frequencies and sounds bright. Pink noise gets 3 dB quieter per octave and sounds softer. Brown noise falls by 6 dB per octave and sounds deep and muffled, like distant surf.

Which noise is best for focus?

It’s a matter of taste. Many people prefer pink or brown noise over white because the high frequencies hiss less. Try the presets and mix in some rain if you like.

Is white noise safe for babies?

Volume, distance and duration matter. A study published in Pediatrics found that sleep machines close to the crib can be too loud. So: quiet, far from the crib, with a timer. When in doubt, ask your pediatrician.

How long does the noise play?

Without a timer it loops endlessly while the page is open. With a timer it fades out gently towards the end and then stops.

Does it work on my phone?

Yes, in current versions of Chrome, Safari, Firefox and Edge. Some phones pause the sound when the screen locks, though – keep the page in the foreground.

Do I need an app or an internet connection?

No app. The page has to load once; after that the sound is computed locally in your browser – no audio is streamed.

Why is it called “brown” noise?

After the botanist Robert Brown and Brownian motion, which is named after him – mathematically, brown noise is integrated white noise. It has nothing to do with the colour brown.

Sources and legal basis

As of: 28 September 2026