How loud is 55 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 55 dB? Between a quiet urban daytime (about 50 dB) and heavy traffic at 300 feet (about 60 dB) outdoors, and about a large business office indoors (between 50 and 60 dB). That is 5 dB above quiet urban daytime, a readily noticeable difference, and 5 dB below heavy traffic at 300 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, 54.8% of the modeled building-façade points have a 24-hour level (CNEL) of 55 dB or more, and 22.1% a Night level (10 pm to 7 am, LAeq) of 55 dB or more (modeled shares, not measurements; map data release of 14 October 2026).
What 55 dB compares with
- Outdoors, between quiet urban daytime (about 50 dB) and heavy traffic at 300 feet (about 60 dB).
- Indoors, about a large business office (between 50 and 60 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 55 dB level means on the Quiet LA map
The map shows 55 dB in two ways. The 24 h value is CNEL, an average over the whole day with evening counted 5 dB higher and night 10 dB higher than day. The Night value is the modeled average between 10 pm and 7 am (LAeq). Neither is 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 55 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 24-hour level at building façades near a freeway stays at or above 55 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. For the Night value the median stays at or above 55 dB out to between 250 m and 500 m.
Aircraft can set the 24 h level too. The map draws airport lines in steps from 55 CNEL up (55, 60, 65, 70, 75), and inside a line the aircraft part of the 24 h value is at least that level. Day, Evening and Night never include aircraft. See LAX and aircraft noise.
Is 55 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 55 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 55 dB)
- Los Angeles County over 24 hours (the 24 h CNEL view; the map legend lists the color of each level, including 55 dB)
- The 405 in the 24-hour view (freeway levels fall with distance)
- Los Angeles International Airport with Aircraft on (the aircraft estimate is in the 24 h colors)
- Van Nuys Airport with Aircraft on (the aircraft estimate is in the 24 h colors)
Common questions
How loud is 55 dB?
Between a quiet urban daytime (about 50 dB) and heavy traffic at 300 feet (about 60 dB) outdoors, and about a large business office indoors (between 50 and 60 dB). This is read by eye from Caltrans’ chart of typical sounds.
What is 55 dB equivalent to?
Outdoors, between quiet urban daytime (about 50 dB) and heavy traffic at 300 feet (about 60 dB). On the chart, 55 dB is 5 dB above quiet urban daytime, a readily noticeable difference, and 5 dB below heavy traffic at 300 feet.
What is an example of 55 dBA?
dBA is the A-weighted decibel, the unit of Caltrans’ chart. Outdoors, between quiet urban daytime (about 50 dB) and heavy traffic at 300 feet (about 60 dB). Indoors, about a large business office (between 50 and 60 dB). The chart is a guide to scale, not a recording, and a sound of 55 dBA depends on how far away it is.
Is 55 dB loud?
On the chart, 55 dB is 5 dB above quiet urban daytime, a readily noticeable difference, and 5 dB below heavy traffic at 300 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 55 dB on the map the same as hearing 55 dB?
No. The map’s 24 h CNEL or 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 55 dB on the Quiet LA map?
Use the links above, then look for the 55 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.