White noise for sleep

White noise is the brightest of the noise colors, and that's exactly why it's so good at covering sharp sounds like voices and barking. Here's how to use it at night without the hiss getting on your nerves.

What white noise actually is

White noise is random sound with equal energy at every frequency, the way white light mixes every color. In practice it sounds like a radio tuned between stations, a hissing radiator, or air rushing out of a vent.

Here's the part most people don't know: "equal at every frequency" does not mean "balanced to your ear." Frequencies are spread out unevenly. The octave from 10,000 to 20,000 Hz contains ten thousand frequencies, while the octave from 100 to 200 Hz contains only a hundred. Give each one the same energy and almost all of the power ends up in the treble. That is why true white noise sounds bright and hissy, and why many "white noise" machines quietly roll off the highs so they're easier to listen to.

Press play on the tile above at a low volume. Then compare it with pink noise, which spreads its energy evenly per octave instead, and you'll hear the difference straight away.

Why white noise is good at its job

The idea behind any steady noise at night is masking. You notice changes in sound much more than steady sound. A dog barking against silence is a big jump. The same bark against a constant hiss is a smaller jump, so it's less likely to pull you awake.

Because white noise is strong in the high frequencies, it's the best of the noise colors at covering sharp, high sounds: voices through a wall, a TV in the next room, barking, a squeaky floor, a partner's phone buzzing. Deeper sounds like brown noise are better at low rumbles such as traffic and bass, but they let voices poke through.

Who it suits (and who it doesn't)

White noise is usually the right first try if:

• The noise that wakes you is high or sharp. Talking, laughter, dogs, a baby monitor in another room.
• You share a wall with neighbors and hear their conversations rather than their footsteps.
• You like a clean, neutral sound that doesn't remind you of anything.

Try something else if white noise sounds harsh or makes you feel on edge. That's common, and it isn't a sign you're "doing it wrong." Pink noise keeps most of the masking with less hiss. A fan sound is another favorite: it's broadband like white noise but softer and more familiar. Our noise color comparison puts all four side by side.

How to set it up for a full night

1. Go quieter than feels natural. White noise sounds louder than it is because of all that treble. Start near silent and raise it a step at a time until the sounds that bother you blend in. Our guide to how loud sleep sounds should be has concrete numbers.

2. Aim the speaker away from your head. Point it at a wall or the door the noise comes through. Bouncing the sound off a wall softens the hiss and spreads it around the room, which masks better than a beam aimed at your pillow.

3. Put the sound between you and the noise. If voices come from the hallway, a speaker near the door works better than one on your nightstand.

4. Decide whether it should stop. Some people wake up when sound suddenly cuts out. Either let it play until morning or use a timer that fades slowly.

5. Give it three nights. A new sound often feels noticeable on night one. Most people stop hearing a steady background within a few nights, the same way you stop hearing a fridge.

White noise variations worth knowing

What the research says (honestly)

Research on noise as a sleep aid is limited. A 2021 systematic review in Sleep Medicine Reviews found the overall quality of evidence for continuous noise was very low and the results were mixed, so nobody can promise you a result.

There are a few interesting individual studies. In a small 2017 trial, 18 healthy young adults slept in a lab on two nights, once with ordinary background noise (about 40 dB) and once with broadband sound played through two speakers at about 46 dB. To make falling asleep harder on purpose, they went to bed 90 minutes earlier than usual. With the sound on, they reached stage 2 sleep sooner (a median reduction of 38%). It's one small lab study with a specific setup, but notice how quiet the sound was: about 6 dB above the room, not a wall of noise.

That's the practical takeaway. White noise works by blending in, so you rarely need it loud.

In the SleepBetter.ai app

White noise is one of the noise sounds in the app, alongside pink, brown and green noise, a box fan and AC hum. You can layer a soft brainwave beat under it with a blend slider, set a sleep timer with a gentle fade, or let it play all night with the phone locked and fade out by your wake-up time. For keeping any sound going until morning with a dark screen, see our all-night setup guide.

A note on babies

White noise for infants comes with its own safety advice. A 2014 Pediatrics study found that infant sleep machines could get loud enough at full volume to exceed the 50 dBA limit recommended for hospital nurseries. If you use any sound for a baby, keep it quiet and well away from the crib, and follow your pediatrician's advice.

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.