Free sleep sounds: noise, rain and a lofi beat

Mix white, pink, brown and green noise, rain and a slow lofi beat, right here in your browser. Free, no sign-up. Each sound comes with a science-backed note on what studies found, and where the evidence is thin.

Updated October 25, 2026By the SleepBetter.ai teamReviewed by the SleepBetter team · Last reviewed October 25, 2026

Brown noise is selected. Press play. It starts quiet.

Tap a sound to add it to the mix, tap again to remove it. Timers fade out slowly over the last part (up to 10 minutes). Brown noise is selected to start.

How to use it

Pick one sound first. Brown noise for traffic and hum, white noise for voices, rain if you want something natural. Add a second layer only if it helps.
Start quiet. The player starts at a low volume on purpose. Raise it until the noises you want to cover are softened, not buried.
Set a timer. Choose 15 to 90 minutes and the sound fades out slowly at the end, or leave it on All night.
Put the device away from the bed. Across the room is better than on the pillow.

Everything you hear is generated live on your device: the noise colours by standard filters, the rain from filtered noise and thousands of randomized droplets, and the lofi beat from an original generative score with soft drums, jazzy seventh chords and tape wobble. Nothing is a recording, so every sound loops without a seam. For more on choosing, see white vs pink vs brown noise and rain vs white noise.

What the science says, sound by sound

We only cite studies we have read. Where there is no research on a sound, we say so. Sound is not a substitute for care if you have insomnia or another sleep disorder.

Brown noise

No direct studies

We found no sleep studies on brown noise specifically. People like it because the low rumble blends with traffic, bass and hum. The broader evidence for steady noise as a sleep aid is very low quality, with mixed results[1].

Try it if: low, booming noises bother you.

Pink noise

Promising, but not this

In a lab study of 13 adults aged 60 to 84, short bursts of pink noise timed by a computer to each person’s slow brain waves boosted slow-wave activity during the bursts (not over the whole night) and went with better word recall the next morning[3]. That is precisely timed pulses, not a steady sound from a speaker, and no study we know of shows continuous pink noise does the same. Evidence for steady noise in general is very low quality[1].

Try it if: white noise sounds too sharp.

White noise

Small studies, mixed

In a lab study of 18 healthy young adults put to bed 90 minutes early (a model of a hard night), steady broadband sound at about 46 dB, against a 40 dB room, helped them reach stage 2 sleep sooner, with a median reduction of 38%[2]. A 2021 review of the wider research rated the evidence for continuous noise as very low quality[1].

Try it if: voices, TV or a partner’s snoring are the problem.

Green noise

No direct studies

Green noise is a popular name, not a research term, and we found no sleep studies on it. Ours is pink noise shaped into a broad band near 500 Hz. The general evidence for steady noise applies: very low quality, mixed results[1].

Try it if: you want something between pink and brown.

Rain

Indirect, awake studies

In an fMRI study of awake volunteers, natural sounds led to brain connectivity the authors link with more outward-focused attention, and higher heart rate variability, compared with artificial sounds[4]. It was not a sleep study. As a steady sound, rain falls under the same very-low-quality evidence for noise and sleep[1].

Try it if: you want something natural with gentle movement.

Lofi beat

Music: moderate evidence

A 2022 Cochrane review of 13 trials with 1,007 adults with sleep complaints found that listening to music for 25 to 60 minutes a day probably improves self-rated sleep quality (moderate certainty); effects on measured sleep were less clear[5]. The trials used calm music in general, not lofi. Our beat follows the same idea: slow (72 BPM), soft, no lyrics and no melody hooks.

Try it if: you prefer music to noise. Set a 30 to 60 minute timer.

Keep the volume low

Sleep sounds play for hours, so level matters more than with a song. Keep it quiet, and keep the speaker away from your head.

World Health Organization: keep personal audio devices at no more than 60% of maximum volume, and keep the average below 80 dB. A safe weekly limit is 80 dB for up to 40 hours; at 90 dB it drops to 4 hours[7]. For scale, the WHO puts a whisper at about 30 dB, a library at 40 dB and normal conversation at about 60 dB.
NIDCD: sounds at or below 70 dBA are unlikely to cause hearing loss, while long or repeated exposure at 85 dBA or above can[8].
Babies: a study in Pediatrics, the American Academy of Pediatrics journal, tested 14 infant sleep machines at full volume. All of them exceeded 50 dBA, the limit recommended for hospital nurseries, at 30 cm, and three exceeded 85 dBA[6]. Keep machines quiet and well away from the crib.
Headphones: iPhone can notify you after more than 80 dB of headphone audio for 40 hours total within 7 days, and Reduce Loud Audio (Settings > Sounds & Haptics > Headphone Safety) can cap the level[9]. A speaker across the room is gentler than earbuds all night.

Questions

Is this sleep sound player free?

Yes. It runs in your browser with no sign-up and no download. Every sound is generated on your device by code using the Web Audio API, so nothing is recorded or streamed, and the player doesn’t use your microphone.

Will it keep playing with my screen locked?

That depends on your browser. Desktop browsers and Chrome on Android usually keep playing in the background. On iPhone, Safari may pause web audio when the screen locks or another app takes over audio. If it stops, turn on Keep screen on (it uses more battery), or use the SleepBetter.ai app, which plays all night with your phone locked.

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

They differ in how energy is spread across pitches. White noise has equal power at every frequency, so it sounds bright and hissy. Pink noise drops by about 3 dB per octave, so it sounds softer and more even. Brown noise drops by about 6 dB per octave, so it sounds like a deep rumble. Our generators measure 0, minus 3 and minus 6 dB per octave.

What is green noise?

Green noise is an informal name, not a research term. Here it means pink noise shaped into a broad band centred near 500 Hz, which many people describe as mellow. We found no sleep studies on it specifically.

Is the lofi beat copyrighted music?

No samples or recordings are used. The lofi beat is an original piece written as code by SleepBetter.ai: about 72 beats per minute, jazzy seventh chords on an electric-piano-style sound, soft brushed drums, gentle tape wobble and light vinyl crackle, with no melody to follow.

How loud should sleep sounds be?

Quiet. Set it just loud enough to soften the noises you want to cover, and keep the speaker away from your pillow. The WHO says to keep personal audio at no more than 60% of maximum volume, and the NIDCD says long or repeated exposure at 85 dBA or above can cause hearing loss. For babies, a 2014 study in Pediatrics found infant sleep machines at full volume exceeded the 50 dBA limit recommended for hospital nurseries at 30 cm.

Is there evidence that sound helps you sleep?

It is mixed. A 2021 review found the evidence that continuous noise helps sleep is very low quality. Music has better evidence: a 2022 Cochrane review of 13 trials found listening to music for 25 to 60 minutes a day probably improves self-rated sleep quality in adults with sleep complaints. If you have insomnia or another sleep disorder, sound is not a substitute for care.

Sources

This page is general information about sound and sleep habits, not medical advice. If poor sleep is affecting your days, talk to a doctor or a sleep specialist.