Decibel Meter Lab
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Private, browser-based sound measurement

Online Decibel Meter – Real‑Time Sound Level Meter

Real-time Sound Meter Dashboard

0.0 dB

Click Start to Measure

Alignment: Default

Status: Ready to measure

Pro Tip: For a more useful comparison, measure for at least 30–60 seconds and compare session averages under similar conditions.

Note: Reference estimate only. Device microphones vary. Use Align reading only with a trusted reference meter; familiar sound examples cannot calibrate this device. Quiet room ≈ 30–40 dB, conversation ≈ 60 dB, traffic ≈ 80 dB.

Measurement Quality

Signal
Low
Stability
Starting
Calibration
Default
Frequency
History (30s)

Measure sound around you in seconds with a free online decibel meter that runs directly in your browser. See a live dB estimate, minimum, average and maximum levels, a 30-second history graph and a real-time frequency spectrum — with no app to install and no account required.

Microphone audio is processed locally on your device. Start the meter only when you are ready; microphone permission is required and your browser prompts if access has not already been granted. Read the Privacy Policy.

Reference estimate, not a certified SPL measurement. Device microphones, gain control and calibration vary. For compliance, legal or precision acoustic work, use a calibrated sound level meter. Read about accuracy and limitations, or learn how to repeat a measurement.

A repeatable five-step method

How to Use the Online Decibel Meter

You do not need special hardware. Any modern phone, tablet or computer with a microphone can run the browser sound meter.

  1. 1

    Start measuring

    Select “Start Measuring” and allow microphone access when your browser asks.

  2. 2

    Hold the device consistently

    Keep the microphone uncovered, avoid direct airflow and use the same distance and orientation if you plan to compare measurements.

  3. 3

    Measure long enough to get context

    A 30–60 second session is more useful than a one-second snapshot because the average and history can smooth out brief spikes.

  4. 4

    Read more than the current number

    Use the live value together with Min, Avg, Max, the frequency spectrum and the 30-second history to understand what changed during the session.

  5. 5

    Stop, compare or save

    Stop the session when finished, align the meter to a trusted reference if needed, and save a report when you want a record of the session.

Everyday reference scale

Decibel Noise Level Chart: What Common Sound Levels Mean

Decibels are logarithmic, so small numerical increases can represent large changes in sound energy. The examples below are approximate real-world references, not targets that every environment should match.

Approximate decibel levels, common examples, perception and context
Approx. levelCommon exampleHow it soundsContext
10 dBNormal breathingBarely audibleVery low level
30 dBSoft whisperQuietWHO example
40 dBLibraryQuiet backgroundWHO example
60 dBNormal conversationModerateUseful everyday reference
80 dBDoorbellLoudWHO safe-listening guidance becomes time-dependent as levels rise
85 dBHeavy traffic inside a carVery loudNIOSH occupational REL: 85 dBA over 8 hours
90 dBShouted conversationVery loudHigher level means less recommended exposure time
100 dBHair dryerExtremely loudWHO example; safe-listening time is short
110 dBShouting in the earExtremely loudVery short exposure times
120 dBNear a sirenPainfully loud for many peopleAvoid unnecessary exposure

Reference examples: WHO Safe Listening Q&A (2026). Occupational threshold note: NIOSH/CDC. Exact readings vary by source, distance and measurement method.

The browser becomes the instrument

What Is an Online Decibel Meter?

An online decibel meter — also called a sound meter, sound level meter, dB meter or noise level meter — uses the microphone already built into your device to estimate the level of sound around you. Instead of installing an app, the measurement runs in the browser.

Decibel Meter Lab is designed for fast environmental checks, before/after comparisons, microphone and room-noise checks, and learning how sound changes over time. It is especially useful when you care about patterns rather than one isolated number: the session average, history graph and frequency spectrum can reveal information a single dB value cannot.

A browser meter is not the same as a calibrated Class 1 or Class 2 sound level meter. Consumer microphones are optimized for communication and media, not certified acoustic measurement. Treat the displayed value as a reference estimate; learn what alignment can and cannot change.

Session averageUnderstand the measurement over time.

History graphSee changes, spikes and quieter periods.

Frequency spectrumSee how sound energy is distributed by frequency.

Interpret the reading correctly

Understanding Decibels

The decibel scale is logarithmic. A 3 dB increase represents roughly twice the sound energy, while a 10 dB increase represents ten times the sound intensity. That is why the difference between 80 dB and 90 dB is much more significant than the numbers look.

+3 dB≈ 2× acoustic energy
+10 dB≈ 10× sound intensity

Perceived loudness is more complicated than acoustic energy and varies with frequency, duration and the listener, so it is better to use the decibel scale as an objective energy-level reference rather than assume every numerical increase sounds the same to everyone.

Sound Meter Accuracy, Calibration and Limitations

The most trustworthy way to use a browser decibel meter is to understand what can change the result. Two devices sitting beside each other can show different numbers even when they hear the same sound. Read the full Accuracy & Limitations guide.

Why readings can differ between devices

Microphone sensitivity

Different phone, laptop and headset microphones convert the same acoustic sound into different electrical/digital levels.

Automatic gain control (AGC)

Some operating systems and devices automatically raise or lower microphone gain.

Noise suppression and voice processing

Communication-focused processing can reduce steady noise or alter peaks.

Frequency response

Microphones do not respond equally to every frequency, so bass-heavy and high-frequency sounds may be represented differently.

Distance and orientation

Moving the device, turning the microphone away from the source or covering it can materially change the reading.

Wind and room reflections

Airflow can overload a microphone, while reflective rooms can change measured levels at different positions.

How to get a more repeatable reading

  • Measure for 30–60 seconds and compare the average, not only the peak.
  • Keep the device, microphone orientation and distance from the sound source consistent.
  • Keep the microphone unobstructed and away from direct airflow.
  • Repeat the measurement two or three times when the result matters.
  • Use the same device for before/after comparisons whenever possible.
  • If you have access to a calibrated reference meter, use the Align Reading control to save a device-specific offset.
Follow the Simple Validation Protocol →

What this tool is good for

  • Everyday noise awareness and room-noise checks.
  • Relative before/after comparisons using the same device and setup.
  • Monitoring trends, bursts and changes during a session.
  • Checking whether a workspace, appliance, fan, speaker or environment is becoming louder or quieter.
  • Learning how sound level and frequency content change together.

What this tool should not replace

  • Certified workplace or occupational noise measurements.
  • Legal or regulatory compliance measurements.
  • Professional acoustic surveys.
  • Medical diagnosis or hearing assessment.
  • Any decision that requires traceable Class 1 or Class 2 instrumentation.
Read the full accuracy and limitations guide →

Real-world comparison workflows

Practical Uses for an Online Sound Meter

Keep the device, distance and session method consistent when the comparison matters.

Home and Everyday Noise

  • Compare appliance, fan or HVAC noise before and after maintenance.
  • Check how much closing a window or door changes traffic noise.
  • Compare different rooms or positions using the same device and measurement method.
  • Document recurring environmental noise with repeatable sessions rather than relying on memory.

Work, Calls and Study

  • Check background noise before an important video call or recording.
  • Compare open-plan work areas and quieter locations.
  • Find when a room becomes noisier during the day by repeating measurements.
  • Use the history graph to see whether noise is steady or caused by short bursts.

Audio, Speakers and Equipment

  • Compare speaker or subwoofer levels from the same listening position.
  • Check whether a PC, fan or other equipment becomes louder under load.
  • Use the spectrum view to distinguish low-frequency rumble from mid/high-frequency noise.
  • Pair the sound meter with the Speaker Test, Bass Test or Tone Generator for deeper troubleshooting.

Environmental Comparisons

  • Compare indoor versus outdoor sound levels.
  • Track traffic, construction or event noise at consistent distances and times.
  • Measure before/after changes such as closing windows, moving equipment or adding noise control.
  • Build a repeatable record over several days when the pattern matters more than one reading.

Build a repeatable record

Using Save Report for Better Noise Documentation

A single dB number is easy to forget and easy to misinterpret. A session report is more useful because it preserves the conditions and statistics you can compare later.

Session summary
Min—
Avg—
Max—
Date and timeSession durationHistory and session information

What the report captures

  • Measurement location.
  • Distance from the main sound source.
  • Device used.
  • Calibration offset, if one was applied.
  • Useful context such as window open/closed, HVAC running, traffic, machinery or crowd activity.
Repeatable comparisons

How to make the report useful

  • Repeat measurements from the same position.
  • Use the same device where possible.
  • Compare averages for steady environmental noise.
  • Use maximum values to identify short peak events, but do not treat one peak as the whole session.
  • For recurring issues, measure at similar times on multiple days before drawing conclusions.

Report privacy: PDFs are generated and downloaded in your browser. They contain session summaries, not raw microphone recordings, and Decibel Meter Lab does not automatically receive a copy. Read the Privacy Policy.

Official guidance, kept distinct

Noise Exposure Guidance: NIOSH, OSHA and WHO Are Not the Same

Many sound-meter pages mix different standards together. They should be separated because they answer different questions.

Occupational recommendation

NIOSH / CDC

85 dBA over 8 hours

3 dB exchange rate. Recommended exposure limit (REL), not a general-environment guarantee of safety.

U.S. workplace regulation

OSHA

90 dBA PEL over 8 hours

85 dBA action level. OSHA uses a 5 dB exchange rate for compliance; do not describe OSHA’s PEL as 85 dBA.

Safe listening / recreational sound

WHO

80 dB up to 40 hours weekly

90 dB about 4 hours weekly. Safe-listening guidance depends on level, duration and frequency of exposure.

Recommended Exposure Duration by Decibel Level: NIOSH 3 dB Exchange Rate

For occupational screening, NIOSH recommends an 8-hour exposure limit of 85 dBA. For every 3 dB increase, the recommended exposure duration is cut in half. The table below illustrates that relationship.

85 dBA

8 hoursNIOSH recommended exposure limit

88 dBA

4 hoursHalf the duration at +3 dB

91 dBA

2 hoursHalf again

94 dBA

60 minutesExposure time falls quickly

97 dBA

30 minutesShort-duration exposure

100 dBA

15 minutesVery limited occupational exposure time

This table is for awareness and education. It does not turn a browser microphone into an occupational dosimeter, and it should not be used for workplace compliance decisions.

Verified against CDC/NIOSH noise guidance, OSHA 29 CFR 1910.95 and WHO Safe Listening guidance.

Level and duration both matter

Why Noise Exposure Matters

Loud sound can affect more than comfort. WHO guidance links excessive noise exposure with hearing impairment and tinnitus, and environmental noise research also identifies sleep disturbance, annoyance and cardiovascular effects among important concerns.

Hearing

Repeated or intense loud-sound exposure can fatigue and eventually damage sensory structures in the ear.

Tinnitus

Ringing or buzzing after loud exposure can be a warning sign that the ears were stressed.

Sleep

Environmental noise can disturb sleep even when it does not fully wake you.

Stress and cardiovascular effects

Long-term environmental noise is associated with broader health impacts in population research.

Concentration and learning

Persistent background noise can make focused tasks more difficult, especially in environments that depend on speech and attention.

If you notice persistent tinnitus, muffled hearing or difficulty understanding speech after loud exposure, seek advice from a qualified hearing professional rather than relying on a browser meter.

Health context verified against WHO Safe Listening and WHO environmental-noise guidance. This information is educational, not diagnostic.

Permission stays under your control

Privacy: Your Microphone Audio Stays in the Browser

Microphone access is one of the most sensitive permissions a website can request, so the measurement flow is designed to be clear. The meter asks for permission only when you start it. The browser controls that permission and shows its own microphone-use indicator.

Decibel Meter Lab processes the live audio stream locally to calculate sound level, history and frequency data. Raw microphone audio is not uploaded as part of the measurement process. A saved report contains session statistics and visual summaries, not a recording of your microphone audio.

You can stop the measurement at any time to release the active microphone stream. See how the browser processes the signal or read the full Privacy Policy.

From microphone signal to useful context

How Does a Browser Sound Meter Work?

In simple terms, the browser listens only after you give permission, turns the microphone signal into a stable level estimate, and draws the history and frequency views on your device.

  1. 01

    Allow the Microphone

    Measurement starts only after you choose Start Measuring and allow access. Technically, the browser uses the secure MediaDevices getUserMedia() API to receive a live microphone stream; HTTPS is required.

  2. 02

    Turn the Signal Into a Stable Level

    The meter looks at short windows of the digital waveform instead of reacting to every sample. It uses Root Mean Square (RMS), a standard way to summarize signal energy, to create a steadier reading.

  3. 03

    Estimate a Real-World dB Reading

    The RMS result first becomes a digital level called dBFS using a logarithmic calculation such as 20 × log10(RMS). dBFS describes the microphone’s digital signal; it is not the same as calibrated sound pressure level (SPL).

    To show an approximate real-world value, the meter applies a reference offset. Microphone sensitivity, hardware gain, automatic gain control (AGC), noise suppression and operating-system processing can all shift the relationship between dBFS and true SPL.

  4. 04

    Build the Spectrum and Session Summary

    A Fast Fourier Transform (FFT) separates the live signal into frequency bands for the spectrum, helping you see whether the sound is concentrated in bass, midrange or treble. The browser’s Web Audio AnalyserNode provides the time- and frequency-domain data.

    During the session, the meter also keeps recent values for the 30-second history and calculates the minimum, average and maximum. These patterns are usually more useful than one momentary number.

Technical references: MDN MediaDevices.getUserMedia and Web Audio API AnalyserNode documentation. Review the measurement methodology and read the accuracy and limitations guide.

Context, not just a number

Why Decibel Meter Lab Gives You More Than a Single dB Number

See more than a momentary reading. Decibel Meter Lab combines live levels, session statistics, frequency data, measurement quality and device alignment to give each measurement useful context. Read why we built the project and see our Editorial Policy for how we source and review guidance.

01
Live dB estimate

See the current sound level update in real time.

02
Min / Avg / Max

Understand the full session instead of one instant.

03
30-second history

Spot bursts, drops and changing background noise.

04
Frequency spectrum

See whether energy is concentrated in bass, midrange or treble.

05
Measurement quality

Identify low signal, unstable readings or possible clipping.

06
Device alignment

Save a calibration offset when you have a trusted reference meter.

07
Private processing

Microphone audio is analyzed locally in the browser rather than uploaded as raw audio.

08
Session reports

Save useful statistics and context when you need to compare measurements later.

Common questions, clear answers

Frequently Asked Questions About Online Decibel Meters

Find clear answers about browser sound measurement, accuracy, calibration, microphone permissions, exposure guidance and how to get more consistent readings.

Is this online decibel meter accurate?

It can provide a useful reference estimate and is strongest for repeatable comparisons on the same device. Absolute accuracy varies because consumer microphones are not individually calibrated as sound level meters. Align Reading can shift the estimate toward a calibrated reference for one setup, but it does not make the browser a certified meter. Use suitable calibrated equipment when an accurate SPL measurement is required. Read about accuracy and limitations. Follow the validation protocol.

Can a phone or laptop really measure decibels?

It can measure the digital microphone signal and estimate a real-world dB value. The browser can calculate RMS, frequency data and relative level very reliably; the uncertain part is the conversion from the device’s digital microphone level to calibrated acoustic SPL. Read about accuracy and limitations.

Why does this meter show a different number from another app or website?

The two tools may use different calibration offsets, smoothing, frequency weighting, microphone constraints or gain behavior. The device and browser can also apply their own audio processing. A difference does not automatically mean one tool is correct and the other is wrong; compare both against a calibrated reference if absolute accuracy matters. Read about accuracy and limitations. Follow the validation protocol.

Why do I need microphone permission?

The browser cannot measure live sound without access to an audio input. Microphone access begins only after you choose to start the meter, and your browser can revoke or block that permission at any time. Read the Privacy Policy.

Does Decibel Meter Lab record or upload my microphone audio?

The Decibel Meter analyzes microphone audio locally without recording or uploading the raw stream. The separate Microphone Test can make a short recording when you press Record Sample; that sample stays in your browser and is not uploaded by the site. Read the Privacy Policy.

What is a normal conversation in decibels?

WHO lists normal conversation at approximately 60 dB as a familiar reference point. Real conversations vary with distance, room acoustics and how loudly people are speaking. Read about accuracy and limitations.

Why is 85 dB important?

NIOSH uses 85 dBA over an 8-hour workday as its recommended occupational exposure limit, with allowable duration halving for every 3 dB increase. OSHA is different: its general-industry permissible exposure limit is 90 dBA over 8 hours, while 85 dBA is the action level for a hearing conservation program.

Can I use this browser sound meter for OSHA or workplace compliance?

No. Official occupational measurements require appropriate calibrated instruments, weighting, response settings, procedures and documentation. Use this browser tool for awareness and screening, not compliance. Read about accuracy and limitations.

What is the difference between dB, dBA and dBC?

dB is a general logarithmic unit. dBA and dBC are frequency-weighted sound-level measurements that apply defined filters before reporting the result. A-weighting reduces the influence of very low and very high frequencies to approximate human hearing sensitivity; C-weighting is flatter and retains more low-frequency energy. A browser meter should not label a value dBA or dBC unless that weighting is actually implemented. Read about accuracy and limitations.

How do I calibrate an online dB meter?

Place your device and a trusted reference sound level meter close together, measure the same steady sound for long enough to get stable averages, then use the Align Reading control to offset the browser reading toward the reference. Save the offset for that specific device and setup. Read about accuracy and limitations. Follow the validation protocol.

Why is my dB reading unusually low, high or unstable?

Check that the correct microphone is selected, the mic is not blocked, and there is no strong airflow. Automatic gain control, noise suppression, Bluetooth headsets and external microphones can also change the signal. For a fair comparison, use the same microphone and browser each time. Read about accuracy and limitations. Follow the validation protocol.

Six focused utilities

Explore More Browser Audio Tools

Decibel Meter Lab is a complete browser audio toolkit. Use the meter for environmental sound, then switch to the specialist tool that matches what you want to test.

Speaker Test

Play controlled channel and test signals to confirm speaker output.

Left/right checks, speaker troubleshooting and setup.
Open Speaker Test

Headphone Test

Check stereo channels and headphone playback using guided audio tests.

Headphones, earbuds and channel verification.
Open Headphone Test

Bass Test

Run low-frequency tones and sweeps to hear how your system handles bass.

Subwoofers, headphones and low-frequency response.
Open Bass Test

Tone Generator

Generate precise test tones at selectable frequencies.

Audio testing, tuning and controlled reference signals.
Open Tone Generator

Microphone Test

Confirm microphone input, level and response before recording or calls.

Mic troubleshooting, calls, streaming and recording setup.
Open Microphone Test

Spectrum Analyzer

Inspect live microphone input or a local audio file across bass, midrange and treble frequencies.

Live microphone analysis, local audio files and frequency peaks.
Open Spectrum Analyzer

Learn About Sound

Practical guides to decibel levels, everyday noise, hearing safety and audio testing.

View All Guides

Visible limits build trust

How Decibel Meter Lab Approaches Measurement

The meter calculates RMS signal energy in short windows, converts the result from a digital dBFS level, and applies a reference offset to show an estimated real-world dB value. FFT frequency data powers the spectrum, while recent samples produce the 30-second history and session statistics. The meter does not label readings dBA or dBC because those defined frequency-weighting filters are not currently applied.

Consumer microphones, AGC, noise suppression, hardware gain and frequency response can shift the result, so Decibel Meter Lab is best for reference checks and repeatable comparisons—not certified Class 1 or Class 2 measurement. Read about accuracy and limitations, or read the full methodology. Exposure guidance is kept separate by source and links directly to NIOSH/CDC, OSHA and WHO below.

Sources checked September 2026. This content is educational and does not replace professional acoustic, workplace-safety or medical advice.

Primary references

Sources Behind the Measurement and Safety Guidance

Use these primary sources to check the exposure, safe-listening, microphone-permission and browser-audio guidance summarized on this page. How we review sources and claims.

NIOSH / CDC

Noise and Hearing Loss

Noise exposure, hearing risk and prevention guidance.

Visit source ↗ NIOSH / CDC

Understand Noise Exposure

Occupational exposure levels, duration and the 3 dB exchange rate.

Visit source ↗ OSHA

Occupational Noise Exposure, 29 CFR 1910.95

U.S. workplace regulation, permissible exposure limit and hearing conservation.

Visit source ↗ WHO

Deafness and Hearing Loss: Safe Listening

Safe-listening guidance for recreational sound level and duration.

Visit source ↗ WHO

Guidance on Environmental Noise

Environmental noise and public-health context.

Visit source ↗ MDN

MediaDevices.getUserMedia()

Browser microphone permission and secure-context requirements.

Visit source ↗ MDN

Web Audio API AnalyserNode

Time-domain and frequency-domain browser audio analysis.

Visit source ↗