White noise for babies: volume, distance and timing

Short answer: white noise can help babies fall asleep, but keep it quiet: about 50 decibels, roughly the sound of a soft shower, measured where your baby lies. Put the speaker across the room, about 7 feet (2 meters) from the crib and never inside it, and use a timer so it turns off after your baby falls asleep rather than running at full volume all night.

Does white noise help babies sleep?

Steady sound masks sudden noises like a door or a dog, and it may remind babies of the constant whoosh of the womb. In a small 1990 study, 80% of newborns fell asleep within five minutes with white noise, against 25% without. It's a tool, not a fix: it won't stop hunger, gas or an overtired baby from waking.

How loud is too loud

A 2014 study in Pediatrics tested 14 infant sleep machines at maximum volume. At 30 cm (about a foot), all of them went over 50 dBA, the limit recommended for hospital nurseries, and three could exceed 85 dBA, the level at which adults are required to wear hearing protection at work over an 8-hour shift. Sound dropped with distance, so the authors advised placing machines as far from the baby as possible and keeping the volume low.

• Aim for about 50 dB at the crib. If you have to raise your voice to talk over it, it's too loud.
• A free sound meter app on your phone, held where your baby's head is, gives a rough reading.
• Start at the lowest volume that masks household noise and go no higher.

Where to put the speaker

As far from your baby's head as the room allows (about 7 feet, or 2 m, is the usual advice), and never in the crib or attached to it. If you use your phone, put it on a shelf or dresser out of reach, with the cable away from the crib.

All night, or just to fall asleep?

The researchers behind the 2014 study suggested running sound for a limited time rather than continuously. A practical approach: play it while your baby falls asleep and for the first sleep cycle, then let it fade out. Some families keep it on all night at a low level to cover early morning noise; if you do, keep it well under 50 dB.

White, pink or brown noise?

• White noise has equal energy at every frequency. It sounds like static or a hiss.
• Pink noise rolls off the highs and sounds softer, like steady rain.
• Brown noise is deeper still, like a strong waterfall or distant thunder.

There's no good evidence that one is better for babies. Many parents find pink or brown gentler to listen to themselves, which matters if it's playing in your room too.

When to stop using it

There's no set age. Many families phase it out in the toddler years by turning it down a little each week. If your child sleeps fine without it on holiday, that's a good sign they're ready.