For healthy sleep, aim for a bedroom that stays quiet, in the 30s of dB on a meter, with few sudden loud noises. The main benchmarks are the WHO’s European night noise guideline, which targets an average of 40 dB outside the home at night, and the U.S. EPA’s 45 dB indoor level for preventing activity interference and annoyance. For babies, the hospital-nursery limit used in infant sleep machine research is 50 dBA.
Sleep noise is not a hearing-damage issue. Levels that disturb sleep are far below the 85 dBA hearing-risk line. The concern is broken sleep, and there the peaks matter as much as the average.
What decibel level is best for sleep? #
| Guideline | Level | What it covers |
|---|---|---|
| WHO Night Noise Guidelines for Europe (2009) | 40 dB Lnight, outside | Target average outdoor night noise to protect health, including children and older people |
| WHO interim target | 55 dB Lnight, outside | A stepping stone for places that can’t reach 40 yet |
| U.S. EPA levels document (1974) | 45 dB indoors | Preventing activity interference and annoyance, including sleep |
| Hospital nursery recommendation | 50 dBA | Cited in research on infant sleep machines |
Sources: WHO Night Noise Guidelines, EPA, and the 2014 infant sleep machine study in Pediatrics.
The WHO figure is measured outside, at the building’s façade. With windows closed, indoor levels are lower. With windows open, they’re closer to the outdoor number. That’s why a bedroom facing a busy road can be fine in winter and terrible in summer.
What does 30, 40 and 50 dB sound like at night? #
| Level | What it’s like |
|---|---|
| Below 30 dB | Very quiet. You notice small sounds: a clock ticking, a partner breathing |
| 30 to 40 dB | Quiet. A quiet library, a calm suburban bedroom at night |
| 40 to 50 dB | Moderate. A fridge hum in the next room, distant traffic, a fan on low |
| 50 to 60 dB | Noticeable. Steady traffic outside an open window, a white noise machine set fairly high |
| 60 dB and up | Too loud for most sleepers. Conversation level, TV |
For comparisons across the full range, see our decibel chart.
Why do sudden noises wake you more than steady ones? #
An average doesn’t tell the whole story. A bedroom that averages 35 dB but gets a 65 dB motorcycle every half hour can be worse for sleep than one that sits at a steady 45. Sudden jumps above the background tend to cause awakenings and shifts into lighter sleep, even when you don’t remember them in the morning.
So when you measure your bedroom, look at three numbers:
- Leq (average): the overall level through the night.
- Max: the loudest events: trucks, doors, a neighbor’s music.
- Min: the steady background, which tells you how much quieter the room could be.
A big gap between min and max means intermittent noise is the problem, and masking or blocking is the fix. A high min means steady noise such as a fan, HVAC or road hum, and reducing the source is the fix.
Is white noise at night safe? #
For adults, generally yes at modest levels. Steady sound can mask the peaks that wake you, which is why many people sleep better with a fan or white noise machine. Keep it at the lowest level that masks the disruptive noise, and put it across the room, not next to your head. Many people set these machines much louder than they need to.
For babies, be more careful. A study in Pediatrics tested 14 infant sleep machines and found that all of them exceeded the 50 dBA hospital nursery limit at 30 cm, and three produced more than 85 dBA at maximum volume. See baby white noise machine volume for safe placement and settings.
How do you make a bedroom quieter? #
- Find the main source. Measure with windows open and closed, and with the fan, air purifier and AC on and off. You’ll often find one source doing most of the damage.
- Seal gaps. Weatherstripping around windows and a sweep under the door cut a surprising amount of airborne noise.
- Add mass or layers at windows. Heavy curtains help a little. Secondary glazing or window inserts help a lot with traffic noise.
- Move the bed. Put your head on the wall farthest from the street or the noisy neighbor.
- Soften the room. Rugs, curtains and upholstered furniture reduce echo, which makes remaining noise less sharp.
- Use earplugs. Foam earplugs are cheap and effective for many sleepers. Make sure you can still hear smoke alarms and anything else you need to wake up for.
- Mask what’s left. Low-level steady sound can cover remaining peaks.
How do you measure noise in your bedroom overnight? #
A phone on the nightstand can log your bedroom through the night. Sound Meter dB is set up for this. Place the phone near where your head goes, microphone uncovered, plugged into a charger, and tap Start. The keep-screen-awake option (on by default) keeps it measuring. When you pause in the morning, the session is saved on the phone with a per-second timeline. You can see when the loud events happened and how loud they were, and export it as CSV if you’re dealing with a landlord or a neighbor. The app pauses if you switch to another app, so leave it open for the night.
Phone meters are less trustworthy at very quiet levels, where a room in the 20s or low 30s can fall toward the limit of what the mic resolves. That’s fine for finding the loud events, which is what matters for sleep. See how accurate phone sound meters are.
If the noise comes from next door, see how to measure neighbor noise. Local rules on nighttime noise vary by city, so check your ordinance before filing a complaint.
Frequently asked questions #
Is 50 dB too loud to sleep? #
For many people, yes. 50 dB is above the EPA’s 45 dB indoor figure and well above a quiet bedroom. Some sleepers are fine at 50 dB of steady fan noise. Few sleep well with 50 dB of irregular noise such as traffic or voices.
Is 40 dB quiet enough for sleep? #
Usually, yes. 40 dB is about a quiet library. The WHO’s 40 dB night target is an outdoor average, so a bedroom measuring 40 dB inside with windows closed is still on the noisy side of ideal, but most people sleep well there.
Does noise affect sleep even if it doesn’t wake you? #
It can. Noise can shift you into lighter sleep stages and raise your heart rate without waking you fully. Protecting health, not only preventing awakenings, is the reason for the WHO’s night noise guideline.
Is sleeping with earplugs every night safe? #
Many people do it without problems. Keep them clean, replace foam plugs regularly, and make sure you can still hear alarms. If you get ear pain, itching or discharge, stop and see a doctor.