White noise safety for babies: volume, distance and when to stop
It is 2am and every creak in the hallway sounds twice as loud.
White noise is not automatically unsafe, but the sound reaching your baby matters. Think in three parts: how loud it is where your baby sleeps, how far the source sits from the cot or bassinet, and how long it plays. Keep it low, place it well away from the sleep space, and avoid assuming it needs to run continuously.
You can also decide not to use it. The NHS says there is no need to keep the house silent while your baby sleeps, and that getting them used to ordinary household sound is fine. White noise is an option, not a requirement.
What the studies actually checked
Researchers have not tested one universal safe setting. They tested particular machines, at particular settings and distances, and found that output varies between devices.
In a 2021 laboratory study of eight infant machines and six phone apps, none exceeded 85 dBA at minimum volume at any tested distance. At maximum volume, 9 of the 14 devices exceeded 85 dBA when measured very close up, at 10 cm; none did at 30 cm or 100 cm in that test. The authors advised against maximum volume and suggested keeping the device well outside the cot, at least 30 cm away.
An earlier AAP-published study tested 14 infant sleep machines at maximum volume at 30, 100 and 200 cm, with an adjustment for a young baby’s ear canal. All 14 were above 50 A-weighted decibels at 30 cm, and three were above 85 A-weighted decibels. The paper discussed the latter alongside adult occupational exposure over eight hours. Its message was to use safer operation, not that every machine behaves the same way.
A 2024 scoping review of 20 studies, including 9,428 children and seven animal-model studies, found that some machines could exceed 91 dB at maximum volume. It concluded that maximum intensity and duration should be limited, while more research is needed on the best intensity and duration. A quiet dial position, on its own, does not tell you what reaches the sleep space.
Decibels, written as dB, describe sound level. You will often see dBA, which means the measurement was A-weighted to reflect how human hearing responds to different pitches. A volume step is not a dB reading at the baby’s ear, and distance changes the sound delivered to the sleep space.
A calmer setup in four steps
1. Start low, and stay below maximum. Choose the lowest setting that still softens sudden household sounds. Avoid maximum volume altogether. A machine with a genuine volume dial, like our BabyCalm white-noise machine, makes a low, deliberate setting easier to find and keep than judging an app's on-screen slider.
2. Check where your baby sleeps, if you can. If you have a sound-level meter, use it at the sleep position as a rough guide, rather than treating the machine’s dial as a measurement. A phone app should not be treated as a precise clinical reading. What matters is the level where the cot or bassinet is, not next to the speaker.
3. Move the source away, and keep it out of the sleep space. Place the speaker as far from the cot or bassinet as is practical in your room, never inside it, attached to it, or tucked under bedding. Keep cables, chargers and power sources well away from the sleeping area, and follow the supplied user guide. The 30 cm figure above was the minimum distance mentioned in one study conclusion, not an ideal to aim for. Farther is the more cautious choice.
4. Limit it to the sleep you need. The American Academy of Pediatrics’ 2023 policy statement suggests, where white noise is used, placing the machine as far as possible from the infant, keeping the volume as low as possible and limiting duration. That might mean using it for settling, rather than assuming it must play without a break. The evidence does not define one timer setting for every family.
The NHS also includes gentle background noise as one possible way to soothe crying, alongside feeding, movement and comfort. It does not describe white noise as a treatment for colic, a guarantee of longer sleep, or something that works for every baby.
What 50 dB and 85 dBA do – and do not – mean
You will see the same two numbers repeated across the internet. They come from different places.
Around 50 dB appears in guides as a cautious working level, linked to the 2014 study and hospital-nursery comparisons. Treat it as a commonly repeated precaution, not a proven home threshold that makes every baby safe below it and unsafe above it. Your room, device and distance all change the reading.
The figure of 85 dBA comes from adult workplaces. The US National Institute for Occupational Safety and Health sets 85 dBA as an eight-hour, time-weighted average for workers, with a 3 dB exchange rate, and expressly says it is not general environmental guidance. Researchers mention it to explain why very loud, close, prolonged output is worth avoiding. It is not a target to play up to at home.
That distinction is easy to blur. Measured device output tells us what some machines did in a test. Occupational limits tell us how workplaces manage adult exposure. Neither gives the UK a machine-specific decibel rule for nurseries, and the NHS pages cited here do not publish one.
The 2024 review does not settle questions about hearing, speech or development; it describes the human and animal evidence as mixed and calls for further research. If your child has a hearing concern, tinnitus, unusual sensitivity to sound or a diagnosed condition, speak to your health visitor, GP or an audiology professional rather than trying to judge it from an article.
When should you stop using white noise?
There is no fixed age in the evidence reviewed here, and none of the UK guidance cited sets one.
You may simply stop when it no longer feels useful. If you want to phase it out, lower the volume a little for a few nights, then shorten how long it plays. This is a family-led routine change, not a medical rule.
If sleep itself is worrying you, or your child seems distressed by sound or silence, that is a separate question from the dial position. Ask your health visitor or GP. This article cannot diagnose hearing or sleep problems.
A quick check before you leave it on
Low, far away, checked where your baby sleeps, and never on maximum. Ordinary household sound is also a calm choice. Pick the setup you can repeat tonight without hovering over the speaker. Leave the maximum setting alone.
Keep reading: if you are wondering whether white noise could help you as well, we looked at the evidence in white noise for adults: does it actually work? For a machine that combines low sound with a soft light, see our WarmWhisper white-noise machine and night light, or compare all our white noise machines.
References
- Hong et al. (2021) – laboratory test of eight infant machines and six apps at minimum and maximum volume, measured at 10, 30 and 100 cm. PubMed record
- Hugh et al. (2014) – test of 14 infant sleep machines at maximum volume at 30, 100 and 200 cm. PubMed record
- American Academy of Pediatrics (2023) – policy statement on preventing excessive noise exposure in infants. AAP Pediatrics
- De Jong et al. (2024) – scoping review of 20 studies on continuous white-noise exposure and childhood development. PubMed record
- NHS – helping your baby to sleep; no need to keep the house silent. NHS guidance
- NHS – soothing a crying baby; gentle background noise as one soothing option. Soothing guidance
- NIOSH / CDC – occupational recommended exposure limit of 85 dBA as an eight-hour average; not a general environmental recommendation. NIOSH science blog