White noise for sleep may help some people by masking sudden sounds like traffic, a barking dog or a snoring partner, but the research is mixed. Two systematic reviews found no strong evidence that it improves sleep. If you want to try it, keep the volume low, use a timer, and judge it by how you feel.
All three are steady hissing or rumbling sounds with no tune or words. The difference is how the sound is spread across high and low pitches. Cleveland Clinic describes them like this:
White noise contains all the frequencies human ears can hear. It sounds a lot like static: busy and a bit harsh.
Pink noise is a muted version of white noise. Lower frequencies are more prominent and higher ones are turned down, so it sounds more like steady rainfall, soft ocean waves or rustling leaves.
Brown noise puts the most emphasis on low frequencies. It has a deep, rumbling, bass-heavy quality, closer to heavy rain, a waterfall or distant thunder.
In everyday life, people also call any steady background sound "white noise," including a fan or an air purifier. The safety tips below apply to all of them.
The honest answer: it seems to help some people, does nothing for others, and the research is not strong either way.
A systematic review in Sleep Medicine Reviews (2021) looked at 38 studies of continuous white noise or similar sound. Results ranged from noise improving sleep to noise disrupting it. Using standard grading criteria, the authors rated the quality of evidence that continuous noise improves sleep as very low. They also cautioned that noise may affect sleep and hearing.
A 2022 systematic review in the Journal of Clinical Sleep Medicine covered 34 studies with 1,103 people. Positive results showed up in 6 of 18 white noise studies, 9 of 11 pink noise studies and 4 of 6 studies that mixed sounds. Even so, the authors concluded there was no strong evidence to support using sound this way. None of the studies reported harm from short-term use.
So pink noise looks a little more promising on paper, but the studies varied a lot in design, and nobody has shown that one color is reliably best. On brown noise, Cleveland Clinic's expert says scientists are still researching its benefits and it is too soon to tell how helpful it can be.
Sound masking makes the most sense when the problem is noise you can't control. For example:
You live on a busy street or near a bar, an airport or a train line.
You have thin walls, noisy neighbors or a partner who snores.
You sleep during the day, when the house and street are louder.
You are sleeping somewhere new, like a hotel, and every small sound wakes you.
It is less likely to be the answer if your room is already quiet and the real problem is a racing mind, a late bedtime or caffeine. In that case, start with this sleep hygiene checklist and these tips to fall asleep faster.
Volume matters more than color. The National Institute on Deafness and Other Communication Disorders (NIDCD) says sounds at or below 70 A-weighted decibels (dBA) are unlikely to cause hearing loss, even after long exposure, while long or repeated exposure at or above 85 dBA can cause hearing loss. Normal conversation is about 60 to 70 dBA. That gives you a simple rule: your sleep sound should be quieter than a normal conversation.
Start at zero and turn it up slowly. Stop as soon as the sounds that bother you blend into the background.
Keep the speaker away from your head. NIDCD's rule of thumb is to avoid noise that is too loud, too close or lasts too long. Put the machine or phone across the room, not on your pillow.
Be careful with earbuds. NIDCD lists music through headphones at maximum volume at 94 to 110 dBA. If you wear headphones in bed, keep the volume very low.
Use a timer. A Cleveland Clinic doctor suggests listening in brief periods of 10 to 15 minutes, and using a timer at bedtime so your ears get a chance to recover. Avoid playing it all night if you can.
Test it for a week or two. Notice how long it seems to take you to fall asleep and how you feel in the morning. If nothing changes, you don't need it.
No study has crowned a winner, so pick the one that sounds most pleasant to you. Try each for a few nights at the same low volume:
If white noise sounds harsh or hissy, try pink.
If pink still feels too bright, try brown for a deeper rumble.
If any sound keeps you alert or irritated, switch it off. Silence is a perfectly good choice.
White noise can hide a sleep problem rather than fix it. The National Heart, Lung, and Blood Institute (NHLBI) lists frequent loud snoring, gasping for air and breathing that starts and stops as common signs of sleep apnea, along with daytime sleepiness. If you or your partner notice these, covering up the snoring is not the answer. Talk to a healthcare provider. Also check in with your doctor if you have trouble sleeping most nights for several weeks, if you nod off while driving, or if you notice ringing in your ears or changes in your hearing.
This is general information, not medical advice. Talk to your doctor or pharmacist about your own situation.
It has not been shown to be harmful at a low volume, and one review found no reported harm from short-term use. But another review cautioned that noise may affect sleep and hearing, so a timer and a volume below conversation level are the safer habit.
In one review, a higher share of pink noise studies had positive results, but the authors still found no strong evidence overall. Use whichever you find more pleasant.
Quieter than a normal conversation, which NIDCD puts at about 60 to 70 dBA. Turn it up only until disruptive sounds fade into the background.
A fan makes a steady sound that many people use in the same way. The same advice applies: keep it away from your head, keep it quiet, and stop if it isn't helping.
Sleepward: Bedtime Routine is an iPhone app for a calmer evening wind-down. It includes white, pink and brown noise with a sleep timer, along with a gradually darkening wind-down screen and an editable routine. It is free with optional Pro purchases, has no accounts or ads, and it does not score or grade your sleep.
Get Sleepward free on the App Store
Noise as a sleep aid: A systematic review (Sleep Medicine Reviews, PubMed)
Systematic review: auditory stimulation and sleep (Journal of Clinical Sleep Medicine, PMC)