SleepHz

White noise: free, no ads, with a sleep timer

White noise is a steady hiss with equal energy at every pitch, like radio static or a running fan. Because it fills the whole range of hearing, it covers sudden sounds like doors, dogs and voices. Press play below for free white noise with no ads, and set Auto-stop so it fades out on its own.

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What white noise does

Kaleidoscope artwork generated from the White White Noise sound
White frequency, visualized. Every SleepHz artwork is generated from the frequency itself: its number sets the symmetry and the pattern.

Sudden sounds wake you because they stand out against silence. White noise raises the background level evenly across every pitch, so a slammed door or a barking dog stands out much less. That's called sound masking.

SleepHz generates white noise live in your browser and softens it slightly at the very top, so it hisses less than a cheap sound machine while still covering the full range.

White noise for babies

White noise is the best-studied noise for infants. In a randomized study of 40 newborns (Spencer et al., Archives of Disease in Childhood, 1990), 80% fell asleep within five minutes with white noise, compared with 25% without it.

Volume matters. When researchers measured 14 infant sleep machines at full volume (Hugh et al., Pediatrics, 2014), every one was louder than the 50 dBA limit recommended for hospital nurseries at 30 cm. Keep it quiet, keep the speaker across the room from the crib, and use Auto-stop.

White noise for focus and studying

A steady hiss can block out chatter in an office, café or dorm. For some people it does more: a 2007 study (Söderlund et al., Journal of Child Psychology and Psychiatry, 2007) found background white noise helped children with ADHD on a memory task, while it slightly hurt the performance of other children. If it distracts you, try softer pink noise.

How to use white noise

  1. Start low, just loud enough to blur the sounds around you.
  2. Use a speaker across the room for sleep, or headphones for focus.
  3. Set Auto-stop for 1 to 8 hours so it fades out on its own.
  4. If it sounds too sharp, switch to pink or brown noise.
Free · No ads · Sleep timerPink noise: free, no ads, with a sleep timer Free · No ads · Sleep timerBrown noise: free, no ads, with a sleep timer White · Pink · Brown · GreenWhite, pink, brown and green noise: what's the difference?

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White noise FAQ

Is it OK to sleep with white noise all night?

Many people do. Keep the volume low and the speaker away from your head, or set Auto-stop to fade it out after you fall asleep.

Is white noise good for babies?

A study of newborns found it helped most of them fall asleep faster. Keep the volume low and the speaker away from the crib.

What's the difference between white noise and pink noise?

White noise has equal energy at every pitch, so it sounds bright. Pink noise turns the highs down, so it sounds softer and fuller.

Does white noise help with focus?

For some people. It masks distracting conversation, and a 2007 study found it helped children with ADHD on a memory task.