How loud is 45 dB?
Updated
Modeled estimates for general information only — not measurements, not a guarantee, and not for legal, medical or real-estate decisions.
How loud is 45 dB? Between a quiet urban nighttime (about 40 dB) and a quiet urban daytime (about 50 dB) outdoors, and a little above a theater or large conference room with only background noise indoors. That is a low level, well under normal speech, which the chart puts near 60 to 65 dB at 3 feet. These are comparisons on Caltrans’ chart of typical sounds, in A-weighted decibels (dBA), and the chart is read by eye, so treat them as about.
In Los Angeles, 62.0% of the modeled building-façade points have a Night level (10 pm to 7 am, LAeq) of 45 dB or more (modeled shares, not measurements; map data release of 14 October 2026).
What 45 dB compares with
- Outdoors, between quiet urban nighttime (about 40 dB) and quiet urban daytime (about 50 dB).
- Indoors, a little above a theater or large conference room with only background noise (about 40 dB).
A change of 3 dB is barely noticeable, 5 dB is readily noticeable and 10 dB is heard as about twice or half as loud (Caltrans). Decibels do not add like ordinary numbers: two equal sounds together are only 3 dB louder than one.
What a 45 dB level means on the Quiet LA map
The map’s Day, Evening and Night values are averages over a period (LAeq), outdoors, 4 m up and 2 m out from a building wall. A Night value of 45 dB is the modeled average between 10 pm and 7 am, not the level of any one sound.
The county shares near the top of this page are modeled, not measurements. Figures from the map data release of 14 October 2026, 14:09 UTC. Each area page gives the same shares for its own area. The points are building façades of every kind, not homes.
Where 45 dB shows up, by source
At 96.1% of the modeled building-façade points in the county, road traffic is the largest modeled contribution to the 24-hour level. In the tables of the six freeway guides, the median Night level at building façades near a freeway stays at or above 45 dB out to at least 1 km, the farthest band in those tables. Past that it falls, and sound walls, buildings and hills move it up or down. See the 405, 101, I-10, 110, I-5 and 710 guides.
Aircraft are never part of the Night value, so a Night level comes from roads and, where the rail model reaches, trains. See train and rail noise.
Is 45 dB loud?
It depends on who is listening, for how long and at what hour, and the map does not rate any level as acceptable or not. Quiet LA gives no medical advice. For the published health benchmark numbers and what they are not, see what 45, 55 and 65 dB mean. A modeled number is typically about 6 dB off at a single address, so a few dB either way is within that error. See Limits.
Open this on the map
Open the map, then open the legend at the right edge of the map to find the color of 45 dB, and select a building to read its modeled values.
- Los Angeles County at night (the Night view; the map legend lists the color of each level, including 45 dB)
Common questions
How loud is 45 dB?
Between a quiet urban nighttime (about 40 dB) and a quiet urban daytime (about 50 dB) outdoors, and a little above a theater or large conference room with only background noise indoors. This is read by eye from Caltrans’ chart of typical sounds.
What is 45 dB equivalent to?
Outdoors, between quiet urban nighttime (about 40 dB) and quiet urban daytime (about 50 dB). On the chart, 45 dB is a low level, well under normal speech, which the chart puts near 60 to 65 dB at 3 feet.
What is an example of 45 dBA?
dBA is the A-weighted decibel, the unit of Caltrans’ chart. Outdoors, between quiet urban nighttime (about 40 dB) and quiet urban daytime (about 50 dB). Indoors, a little above a theater or large conference room with only background noise (about 40 dB). The chart is a guide to scale, not a recording, and a sound of 45 dBA depends on how far away it is.
Is 45 dB loud?
On the chart, 45 dB is a low level, well under normal speech, which the chart puts near 60 to 65 dB at 3 feet. Whether it is loud depends on who is listening, for how long and at what hour; the map does not rate any level as acceptable or not, and Quiet LA gives no medical advice.
Is 45 dB on the map the same as hearing 45 dB?
No. The map’s Night value is a modeled average over a period, not the level of one sound, and it is an estimate, not a measurement. At a single address it is typically about 6 dB off.
Where can I see 45 dB on the Quiet LA map?
Use the links above, then look for the 45 dB color in the legend. You can also look up one address with the search box. See how to look up an address.
More on the scale: what 45, 55 and 65 dB mean. How the numbers are made: How it’s made and Sources & methods. What they can and cannot be used for: Limits.
Sources
- Caltrans: Technical Noise Supplement to the Traffic Noise Analysis Protocol (September 2013) Table 2-5 (typical noise levels), Table 2-10 (perceived change) and Table 2-11 (noise descriptors, including CNEL). Checked 21 October 2026.