Relax and sleep sounds
Turn on the sounds you like, set each one's volume, and add a sleep timer that fades out gently. Every sound is made live in your browser: no recordings, nothing streamed.
Browsers only allow sound after you tap: press play or any sound to start.
This browser can't make sound with the Web Audio API, so the mixer can't play here. Try an up-to-date browser.
Your mix (which sounds, their volumes and your focus settings) is saved in this browser on this device only, so it is ready next time. Nothing is uploaded. Sound may keep playing when the screen locks where your browser allows it; you can pause it from the lock screen.
Focus mode (Pomodoro)
Your mix plays while you focus. At each break it fades down or switches to a softer sound, with a gentle chime at every switch.
Need a stopwatch, a plain countdown or laps? Use the full stopwatch and timer.
Babies and white noise: keep it low and far away
A 2014 study in Pediatrics, the journal of the American Academy of Pediatrics, tested 14 infant sleep machines at full volume. At 30 cm, all 14 were louder than 50 dB, the recommended noise limit for babies in hospital nurseries. At 2 m, 13 of the 14 still were, and 3 could pass 85 dB, a level that can harm hearing over a long night.
- Keep the volume well below 50 dB at the baby's ear: just loud enough to soften sudden noises.
- Put the phone or speaker as far from the cot as you can (at least 2 m), never in or on the cot. A safe cot is kept clear of objects.
- Use it for shorter spells: the sleep timer above fades it out once the baby is asleep.
- A phone's volume bar is not a decibel reading. For a rough check at the cot, use the noise level tool.
For adults too: keep it just loud enough to mask other noise, and lower with earphones. This is general information, not medical advice: ask your paediatrician or doctor about your own case.
How the sounds are made
White noise has equal energy at every pitch, so it hisses. Pink noise has equal energy in every octave, so it sounds softer, like steady rain. Brown noise leans even further to the low end, like a distant rumble.
Rain, wind, waves and the stream all start as noise. Filters cut it to the right pitch, and slow, random changes in loudness make waves swell and wind gust.
Droplets, crackles, bubbles and cricket chirps are tiny sounds scheduled at random moments, so the mix never loops in an obvious way.
Sources: Hugh SC, Wolter NE, Propst EJ, Gordon KA, Cushing SL, Papsin BC, "Infant Sleep Machines and Hazardous Sound Pressure Levels", Pediatrics 2014;133(4):677–681 (doi:10.1542/peds.2013-3617): 14 machines at maximum volume, all above 50 dBA at 30 cm, 13 of 14 above it at 200 cm, 3 above 85 dBA; the authors advise using them as far from the baby as possible, at the lowest volume and for less time, as reported by CBC News and Children's Hospital of Philadelphia. American Academy of Pediatrics, "Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment" (Moon RY et al., Pediatrics 2022), and its healthychildren.org summary: keep soft objects and loose items out of the baby's sleep area. Pomodoro timings (25 minutes of focus, 5-minute breaks, a longer break after four rounds) follow Francesco Cirillo's Pomodoro Technique. Noise colours are standard acoustics definitions. Browser behaviour: MDN Web Docs on the Web Audio API, autoplay rules and the Media Session API.