Sound Meter
Measures sound & noise via your device microphone in dB unit
Min
— dB
Max
— dB
Normalized
0 / 100
Average
— dB
Calibration
Sound
-90.0
dB
Quiet
Initializing microphone...
Noise
-90.0
dB
Sound Meter FAQ
How accurate is the dB reading?
The readings are relative, not calibrated to professional SPL meter standards. Results vary by microphone sensitivity and hardware. Use the calibration control to offset the reading by ±20 dB if you have a reference source to calibrate against. For scientific measurements, use a dedicated SPL meter.
Why is my microphone level so low or high?
Microphone sensitivity varies widely between devices — a laptop mic, phone mic, and external USB mic all have different levels. Use the calibration control to adjust the offset so readings match your expectations. Increasing the +dB offset boosts reported levels; negative values reduce them.
What do the colour zones mean?
Blue = Quiet (below -60 dB) — near silence. Green = Normal (-60 to -45 dB) — quiet conversation. Yellow = Loud (-45 to -30 dB) — normal conversation, TV. Orange = Very Loud (-30 to -15 dB) — shouting, music. Red = Danger (above -15 dB) — could cause hearing damage with prolonged exposure.
Is my audio recorded or sent anywhere?
No. This tool processes audio entirely in your browser using the Web Audio API — no audio data is recorded, stored, or transmitted anywhere. Only the computed amplitude values (numbers) are used for display, and they are discarded when you stop or close the page.
Why does the graph only go back 30 seconds?
The scrolling graph is designed for a quick snapshot of recent ambient noise. Storing longer history would increase memory usage significantly. If you need a longer log, note the Min/Max/Average stats which accumulate for your entire session.
What is "Normalized" in the stats?
Normalized is the current dB level expressed as a 0–100 percentage of the full measurement range (from -90 dB silence to 0 dB maximum). It's a simpler way to see relative loudness without needing to interpret negative dB values.
About Sound Meter
This free online sound meter measures real-time ambient noise and sound levels in decibels (dB) directly in your browser using your device microphone — no app download or signup required. It uses the Web Audio API to capture and process audio, displaying live readings with a color-coded zone graph updated every frame.
- Real-time dB readings for both sound level and noise level
- 30-second scrolling bar graph colored by zone (Quiet → Danger)
- Tracks minimum, maximum, and average levels for your session
- Calibration offset (±20 dB) to match hardware microphone sensitivity
- Normalized 0–100 score for quick relative loudness reference
- All processing is local — no audio is recorded or transmitted
How to Use the Online Sound Meter
- 1
Allow microphone access
The page automatically requests microphone permission when it loads. Click "Allow" in your browser's permission prompt to start measuring.
- 2
Read the live dB values
The Sound level (left) and Noise level (right) panels update in real time. The color changes from blue (quiet) to red (danger) as levels rise.
- 3
Watch the 30-second graph
The bar chart scrolls right-to-left, showing one bar per second. Bar height and color reflect the recorded level at that moment.
- 4
Check the stats toolbar
The top bar shows Min, Max, Normalized, and Average values accumulated since the session started. Click "Reset stats" to clear and start fresh.
- 5
Calibrate if needed
Use the + / − buttons in the Calibration cell to shift readings up or down by up to ±20 dB to compensate for your microphone's sensitivity.
Tip: For the most accurate relative readings, hold your device still and avoid covering the microphone. Laptop microphones are usually located near the keyboard or speaker grille.
Common Use Cases
Office & Workspace Noise
- • Check if your open-plan office meets safe working levels
- • Compare noise before and after acoustic panels are installed
- • Identify the loudest times of day for focused work
Home & Environment Monitoring
- • Measure street noise through windows before renting
- • Check whether a baby's room stays below 50 dB at night
- • Monitor HVAC or appliance noise levels over time
Events & Venues
- • Verify that a venue's music stays within permitted limits
- • Check classroom noise levels during lessons
- • Monitor crowd noise at sports events or conferences
Audio & Podcast Production
- • Check ambient noise floor before recording a podcast
- • Identify background noise sources (HVAC, traffic, fans)
- • Set a baseline to choose the right noise gate threshold
Hearing Health Awareness
- • Spot environments louder than 85 dB — the safe exposure limit
- • Decide when to wear ear protection at concerts or workshops
- • Educate children about noise-induced hearing risk
Testing & Troubleshooting
- • Confirm a microphone is working before a video call
- • Test soundproofing effectiveness after DIY treatment
- • Quick sanity-check without installing a native app