DecibelMap is a free, open, collaborative noise map. Anyone can measure and share real noise levels from anywhere on Earth. No audio is ever recorded — only the decibel reading is stored.
decibelmap.com · v7.0
📖 How to Use DecibelMap
🎤 Taking a Reading
Tap the green microphone button at the bottom center
Grant microphone permission when prompted
Hold still for 5 seconds while the app measures
Your reading is automatically pinned to your GPS location
The reading syncs to the global map for everyone to see
📍 Where to Stand
Sidewalk level — hold phone at chest height, don't pocket it
Mid-block for residential streets (not at intersections — those are always louder)
Storefront level for commercial areas (captures what a pedestrian hears)
Center of parks (edges pick up road noise)
Face the dominant noise source — road, construction, venue
Stay still and silent during the 5-second recording. Don't talk, walk, or shift the phone.
⏱ How Many Readings Per Location
A single reading is a snapshot. For truly useful data, the same spot needs readings at different times:
Morning — 7:00–9:00 AM (commute, garbage trucks, schools)
Midday — 11:00 AM–1:00 PM (baseline activity)
Evening rush — 5:00–7:00 PM (peak traffic)
Night — 9:00–11:00 PM (nightlife, quiet residential)
Each reading takes about 10 seconds total (walk up, stand still, record). You can cover 20+ locations in a 30-minute walk.
📊 Reference: What dB Levels Mean
dB Level
Sounds Like
Impact
20–35
Rustling leaves, quiet bedroom
Ideal for sleep
35–45
Library, quiet suburb at night
Peaceful
45–55
Light rain, quiet office
Comfortable
55–65
Normal conversation, AC unit
Moderate — can concentrate
65–75
Busy road, vacuum cleaner
Annoying — hard to sleep
75–85
Highway, loud restaurant
Stressful — hearing risk over time
85+
Concert, power tools, subway
Dangerous — limit exposure
✅ Good Readings
Residential street at 10 PM Tuesday (tells renters about sleep conditions)
Restaurant row at 8 PM Friday (apartment-above-retail reality check)
Near a freeway on-ramp at 7 AM (commute noise exposure)
School zone at 3 PM (pickup chaos level)
Park at 6 AM (baseline quiet)
❌ Bad Readings
These produce misleading data — don't do them:
Inside a car (engine + cabin isolation = wrong number)
Inside a building (you're measuring the building, not the street)
While you're talking or playing music
During a one-time event (parade, construction, emergency)
With phone in your pocket or pressed against your body
📱 Phone Calibration
Different phone microphones have different sensitivity levels. DecibelMap automatically detects your phone model and adjusts the calibration so your readings are accurate out of the box.
Supported devices include iPhone, Samsung Galaxy, Google Pixel, Sony Xperia, OnePlus, Xiaomi, Huawei, Motorola, LG, OPPO, Nokia, and more. If your phone isn't specifically recognized, a general Android or desktop calibration is applied automatically.
Use these benchmarks to verify your phone reads correctly:
A dead-quiet room at night should read 30-40 dB
A busy urban street should read 65-75 dB
A freeway edge should read 75-85 dB
🗺️ Map Controls
Search bar — type any address, city, or landmark
📍 button — centers on your current location
+/− — zoom in and out
◐ — show/hide the noise level legend
Tap any dot — see the reading details
Pinch to zoom — works like any map
🔒 Privacy
DecibelMap records only the decibel number and your GPS coordinates. No audio is ever captured, transmitted, or stored. Your microphone is active for exactly 5 seconds during a reading, then immediately released.