Application guide
How Loud Should a Baby's Room Be
The guideline most parents are looking for is a single number, but it only means anything together with the place the measurement was taken. Here is the number, the position, and how to check it.
Free to download. Informational only, and not a medical device.The guideline
50 dB, measured at the crib
The American Academy of Pediatrics recommends that sound machines in hospital newborn nurseries be kept at or below 50 dB, and the widely repeated placement advice that follows from it is to keep a machine at least 7 feet, about two metres, from the crib. Fifty decibels is quiet: roughly a fridge in the next room, and well under normal conversation.
The distance matters as much as the setting on the machine. Because level falls off with distance, the same device can be comfortably under 50 dB across the room and well over it on the rail of the crib. Researchers have also pointed out that a machine running at 85 dB for eight hours or more would exceed the exposure limits used for adults, which is the reason the placement advice exists at all.
Guidance as reported by Happiest Baby and SNOOZ. dB Decibel is not affiliated with the American Academy of Pediatrics, and nothing here is medical advice. Ask your pediatrician about your own child.
Taking the reading
Measure where the head is, not where you are standing
Position
- Hold the phone inside the crib, at the height and place the baby's head rests. Not on the changing table, not by the door.
- Take the phone out of its case and keep a finger off the bottom edge, where the primary microphone sits.
- Let the reading settle for twenty or thirty seconds and read the average, not the first number that appears.
- Repeat with the machine at the distance you actually intend to leave it, then move it and measure again. Two readings tell you what the distance is worth.
Why the near silence flag matters here
A nursery with the machine off often sits in the thirties in dB(A), which is right at the edge of what a phone microphone can resolve. That is precisely the range where meters without a floor check start inventing numbers in the fifties.
When dB Decibel reports near silence it means the room is quieter than the phone can measure. For a nursery that is the answer you were hoping for, and an honest one.
The honest part
What this measurement is worth
A phone reading is good enough to answer a comparative question: is the machine louder at the crib than across the room, is this setting quieter than that one, does closing the door help. Those are the questions parents actually have, and a phone answers them well.
It is not good enough to certify that a room is within a clinical guideline. The uncertainty on an uncalibrated phone microphone is of the same order as the margin you are trying to check, so if you measure 49 dB you have not proven you are under 50. Leave room: aim comfortably below the guideline rather than at it, and use the guided calibration first so the offset is at least the right one for your phone.
What this app is not. Readings are approximate (±dB) and come from an uncalibrated phone microphone. dB Decibel is an environmental sound measurement tool. It is not a certified sound level meter, not a dosimeter, not hearing protection and not a medical device, and it is not suitable for occupational, regulatory or legal compliance. That wording is taken from the disclaimers inside the app itself. This is not medical advice and dB Decibel is not a hearing screening tool. Concerns about a child's hearing belong with a pediatrician or an audiologist.
Related measurements
The same percentile figures that describe a nursery describe your own room: measuring bedroom noise at night covers L90, L10 and the overnight timeline. If the noise is arriving from a neighbor rather than from inside the flat, see documenting a noisy neighbor.
Get the app
Check the crib in a couple of minutes
The free version gives you the live dB(A) reading, the session average, the labeled reference scale and the near silence flag, which is everything this particular check needs. No account, no connection required, and audio is never recorded or sent.
Free to download. iPhone, iOS 18 or newer. Optional one time Pro unlock, no subscription.Keep reading