One sound away from focus
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Deep work
Brown noise masks office chatter and keeps your attention from snagging on every little sound.
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Sleep
Rain + brown noise with the 8-hour timer is a classic baby-sleep and light-sleeper combo.
Free · No app · Plays in the background
White noise machine, rain & focus sounds
Mix white, pink and brown noise with rain, ocean and fan sounds. Set a sleep timer and let it run — generated live in your browser, nothing streamed.
Tip: press Space to play/pause. Your mix is remembered for next time.
🔒 Sounds are synthesized by your browser — no files, no streaming, works offline.
White, pink and brown are different things
The colours describe how energy is distributed across frequency. White noise has equal power at every frequency, which sounds bright and hissy — like an untuned radio — because human hearing bands cover progressively wider frequency ranges as pitch rises, so the upper octaves carry disproportionate energy.
Pink noise reduces power by 3 dB per octave, giving equal energy per octave rather than per hertz. This matches the way hearing is organised, so pink noise sounds balanced and natural — closer to rainfall or wind. It occurs widely in nature and is generally the more comfortable choice for long listening.
Brown noise, sometimes called red, falls by 6 dB per octave, emphasising low frequencies further. It sounds like a deep rumble, a waterfall or heavy surf, and many people find it the least fatiguing of the three. There is no correct choice; the difference is in spectral balance rather than in effectiveness.
The fullscreen visuals follow the mix
Full screen turns the page into an ambient scene built from whatever you have switched on. Each sound has its own look — rain falls in streaks and leaves ripples, ocean rolls as layered swells, brown noise drifts as slow warm masses, pink shimmers, white breaks into fine static, and the fan sweeps in slow rotation. They are blended together rather than one being picked: rain over ocean shows streaks falling onto swells, and the balance you set with the per-sound sliders is the balance you see.
The motion is driven by the audio itself rather than a free-running clock. An analyser reads the master output, so the ocean's swells rise and fall with the slow modulation actually being synthesised instead of merely close to it. Pause, and the scene settles to a still background rather than animating in silence.
It only runs while you are in full screen, and it stops if you switch tabs. That is deliberate: this is a tool people leave playing for eight hours overnight, and animating a canvas nobody is looking at is the fastest way to flatten a phone battery. Outside full screen, nothing is drawn at all.
How masking actually works
Noise works by auditory masking: a broadband sound raises the threshold at which other sounds become audible, so intermittent noises no longer stand out against silence. This is why it helps with a neighbour's television or traffic — the interruptions are what disturb attention, and masking reduces their salience rather than their volume.
Masking is most effective when the noise overlaps in frequency with what you want to obscure. Speech occupies roughly 250 Hz to 6 kHz, so pink noise is well suited to masking conversation, while low-frequency brown noise leaves speech more audible. Conversely, brown noise is better against low rumble.
The important limit is that masking cannot remove a sound that is louder than the masker. Raising the noise to cover a loud disturbance means listening at a level that is itself harmful, which is the wrong trade — see below.
Evidence, volume and hearing safety
The research on noise for concentration and sleep is genuinely mixed. Some studies report improved sleep onset in noisy environments and modest attention benefits for some people; others find no effect or slight impairment, particularly for tasks involving language. A 2021 systematic review of noise for sleep concluded the evidence was of low quality and inconsistent, and cautioned against broad recommendations.
Individual variation is large and real. Some people concentrate markedly better with broadband noise, and others find it degrades performance. Trying it is reasonable; assuming it works because it is widely recommended is not.
Volume is the one point where caution genuinely matters. Continuous exposure above roughly 70 dBA over a day carries cumulative hearing risk, and overnight playback for eight hours is exactly the exposure pattern that accumulates. Keep it as quiet as achieves the masking you need, prefer speakers to headphones for sleep, and be aware that guidance for infant sleep machines is stricter still — several studies have found popular devices capable of exceeding safe levels at close range. If sleep problems persist, that is a matter for a clinician rather than a sound generator.
White noise FAQ
Which noise color should I use?
Try brown first — most people find it least fatiguing for long sessions. Use white when you need to mask speech (open offices), and pink as the middle ground. There's no wrong answer; whatever fades into the background for you is right.
Will it drain my battery?
Very little — the synthesis is a few simple filters, far lighter than streaming audio or video. The fullscreen visuals do cost more, so they only run while full screen is open and stop as soon as you leave it or switch tabs. Playing with the screen off costs almost nothing.
What are the fullscreen visuals?
An ambient scene built from the sounds you have on. Rain falls in streaks, ocean rolls in layered swells, brown noise drifts as slow warm masses, white breaks into fine static, and the fan sweeps in slow rotation — blended together and weighted by your per-sound sliders, so a rain-over-ocean mix shows both. The movement is driven by an analyser on the real audio, so what you see follows what you hear.
Can I mix several sounds?
Yes — toggle any combination and balance them with the per-sound sliders. Rain over brown noise is the most popular mix.
Why white noise at all?
Steady broadband sound raises your auditory floor, so sudden noises (doors, chatter, traffic) stand out less and interrupt you less — that's the whole trick.
What is the difference between white, pink and brown noise?
How energy is spread across frequency. White is equal per hertz and sounds hissy, pink falls 3 dB per octave and sounds balanced, brown falls 6 dB per octave and sounds like deep rumble. Preference is individual.
Is it safe to play noise all night?
Keep the volume low. Continuous exposure above roughly 70 dBA accumulates hearing risk over a day, and overnight playback is exactly that pattern. Use the quietest level that masks what you need, and prefer speakers to headphones.
Is this a real white noise machine?
It does the same job as a hardware white noise machine, with one difference: the sound is generated live in your browser rather than played from a recording, so it never loops or repeats and there is nothing to download. Audio keeps playing while the tab is in the background. What it cannot do is run with the browser closed — for that you still want a physical machine.