Why white noise calms babies
The womb is not quiet. Blood flow, the mother’s heartbeat and digestion produce a constant whooshing sound, which ultrasound microphones have measured at well above normal room level. A silent nursery is a big change from that, and steady noise can feel familiar and reassuring.
White noise also masks the household sounds, such as doors, siblings and traffic, that can jolt a baby out of light sleep. Babies spend more time in light sleep than adults, so they wake more easily.
The best-known study is Spencer and colleagues, published in Archives of Disease in Childhood in 1990. Among 40 newborns, 80 percent of those who heard white noise fell asleep within five minutes, compared with 25 percent of those who did not. Later work has been more mixed, but most pediatric advice today accepts white noise as a reasonable tool if it is used safely.
Safe use: volume, distance and time
In 2014 researchers in Toronto (Hugh and colleagues, Pediatrics) tested 14 infant sleep machines. At maximum volume, every one exceeded 50 decibels, the level recommended for hospital nurseries, when measured 1 meter away, and three exceeded 85 decibels at 30 centimeters, the workplace limit for adults over an 8-hour shift. Babies’ ear canals are small, which makes the same sound more intense at the eardrum.
- Keep the speaker at least 2 meters (about 7 feet) from the crib, never inside it or on the rail.
- Keep it quiet: roughly the level of a soft shower, about 50 decibels at the crib. A phone sound meter app can check this.
- Start the sound before sleep and use the timer, or keep it low enough that all-night use is comfortable for an adult sitting by the crib.
- Do not use earbuds or headphones on a baby.
- Never let the device or cable be within the baby’s reach.
The full reasoning, including what pediatric bodies say, is in is white noise safe for babies?.
Which sound to choose for a baby
| Sound | Best for | Notes |
|---|---|---|
| White noise + heartbeat (default) | Newborns | Closest to womb sounds; the heartbeat is a calm 68 beats per minute |
| Pink noise | Older babies, light sleepers | Softer than white, less hiss |
| Brown noise | Noisy streets, flights | Deep; masks rumble and engines |
| Rain or fan | Toddlers | Familiar, natural, easy to keep using for years |
Using the player for a baby
- The default mix lowers the brightness with the Tone control to keep it soft. Leave the heartbeat on for newborns; turn it off as your baby grows.
- Turn on Keep screen on so a phone does not stop the sound, or download a 10 minute loop and play it on repeat from any device.
- Turn the device volume down first, then raise it slowly. The play button always fades in over a second.
- Want to wean off it later? Lower the volume a little each week until it is off.
Frequently asked questions
Is white noise safe for newborns?
It can be, if it is quiet and far enough away. Keep the source at least 2 meters from the crib, at about the level of a soft shower, and never place it in the crib. The danger is in loud machines placed close to a baby for long periods.
How loud should white noise be for a baby?
Around 50 decibels at the crib, roughly a quiet conversation heard from across a room or a soft shower. If you need to raise your voice to be heard over it, it is too loud.
Should white noise play all night for a baby?
Many parents use it all night at a low volume and pediatric advice generally allows this when the level is low and the source is far from the crib. Alternatively, use the timer to play it while your baby falls asleep.
Will my baby become dependent on white noise?
Babies associate it with sleep, like a lullaby or a dark room. That makes it a helpful cue, and it is easy to phase out later by lowering the volume gradually over a week or two.
Pink or white noise for a baby?
Either works. White noise is closer to the shushing many parents do naturally; pink noise is softer. Choose whichever seems to settle your baby, at the same safe volume.