Decibel Meter FAQ

A decibel meter, also called a sound level meter or noise meter, measures the intensity of sound in an environment and reports it in decibels (dB). An online decibel meter does the same job in your browser using your device’s microphone — no hardware or app required.

When you press Start Measuring, the browser requests microphone access, then captures the audio and analyzes it in real time using the Web Audio API. The signal amplitude is converted into a decibel value and displayed live, together with minimum, average, maximum, peak, and Leq statistics. All processing happens locally on your device.

Yes. Every smartphone has a microphone, and this online decibel meter uses it to estimate the sound level around you. Results are convenient for everyday checks — typical accuracy is within a few dB in the mid-range — though readings vary between devices and benefit from calibration. See the phone decibel meter guide for details.

Yes. The decibel meter is completely free: no downloads, sign-ups, subscriptions, or hidden features. It runs in your browser and works on phones, tablets, and computers.

No. The meter runs entirely in your browser, so there is nothing to install. Just open the page and allow microphone access when your browser asks for permission.

Yes. The microphone is the sensor — the meter captures sound through it and converts it to a dB reading in real time. Browsers always ask for permission first as a privacy safeguard. In this tool, the audio is processed locally on your device and is never uploaded or recorded.

A well-built online decibel meter gives useful estimates — typically within a few dB of a professional meter in the 40–90 dB range when used carefully. Consumer microphones are not calibrated instruments, so readings are for reference and education, not certified measurements. The accuracy guide explains what affects readings in detail.

A quiet room is typically around 30–40 dB, normal conversation measures roughly 60 dB, and busy street traffic sits in the 70–80 dB range. Typical everyday environments usually stay below 85 dB.

30 dB is very quiet — a soft whisper, a quiet library, or a bedroom at night. It is roughly the level of a refrigerator hum in a silent room and is safe for unlimited exposure.

60 dB is normal conversation at arm’s length, background music, or a running dishwasher. It is the everyday level of a typical home during the day and is safe for any duration.

70 dB is a busy street, a vacuum cleaner, or a loud conversation. Levels below 70 dB are generally considered safe regardless of duration; this is where "noticeably loud" begins.

80 dB is heavy traffic, a noisy restaurant, or an alarm clock. It is loud enough to make conversation effortful, but brief exposure is not a concern for most people.

85 dB is the level where prolonged exposure starts to matter: NIOSH recommends no more than about eight hours at 85 dBA. A noisy lawnmower or blender sits near here, and the safe duration halves with every 3 dB increase.

100 dB is a motorcycle, chainsaw, jackhammer, or headphones at maximum volume. The recommended exposure is roughly 15 minutes. It is common at live events and a frequent cause of ringing ears afterwards.

dB is the raw decibel reading of sound pressure level. dBA applies A-weighting, a frequency filter that mirrors the sensitivity of human hearing, so dBA values reflect how loud a sound actually sounds to people. dBA is the standard measure for noise exposure.

A-weighting is a frequency filter that mimics the human ear’s sensitivity: it attenuates very low and very high frequencies and passes the speech range unchanged. A-weighted readings (dBA) approximate perceived loudness and are the standard for environmental and occupational noise measurement.

C-weighting (dBC) is a much flatter curve that preserves low-frequency content, matching perception for loud, bass-heavy sound such as concerts, engines, and machinery. Z-weighting (dBZ) is a flat response with no frequency correction at all, used for raw acoustic measurements. The dB vs dBA guide compares all three.

Leq (equivalent continuous sound level) is the average sound energy over the whole measurement session. Unlike a simple average, it correctly accounts for energy, which makes it the metric professionals use to assess noise exposure.

RMS (root mean square) is the effective continuous level of a signal — it averages the waveform energy over a short window. It tracks perceived loudness better than instantaneous peaks and is the basis for the current dB reading on most sound level meters.

Yes. The meter measures whatever sound is present, so background or ambient noise is exactly what it captures. For a background noise reading, measure during a quiet moment, keep the device still, and use the minimum or average reading rather than single instants.

Place the device where people actually sit or stand, keep the microphone unobstructed, and measure for at least a minute while no one talks. Use the average or Leq reading and compare it with the common sounds chart. The how-to-measure guide walks through the full workflow.

Measure at the wall or floor where the noise enters, at ear height, for at least 10–15 minutes to capture the pattern. Note the maximum for short events like bass hits and the Leq for overall levels. Keep the microphone clear of the wall to avoid contact vibration, and remember that phone readings are estimates — not evidence.

Place the device at a student’s desk height in the center of the room, away from projectors and air vents, and measure across a full lesson period. The average and Leq tell you the typical level students experience; spikes above 80 dB show disruptive events.

Measure at ear height in the actual work position for the full shift or task period. Use Leq to estimate exposure and check it against limits (for example, 85 dBA over 8 hours). For formal compliance assessments you must use a certified sound level meter — see the noise exposure guide.

Yes. Place the device about one meter from the speaker, pointing at it, and measure during music playback. The average gives the typical level; the peak shows the loudest transients. Keep in mind that consumer microphones under-report deep bass, so subwoofer-heavy content reads lower than it sounds.

Play a known reference sound, such as a 94 dB calibration tone from a trusted source, note what the meter reads, then enter both values in the Calibrate dialog — the offset is calculated automatically. Calibration improves consistency but cannot make a consumer microphone a laboratory instrument. See the calibration guide for the full method.

Phone microphones have different sensitivities and frequency responses, and devices apply different amounts of automatic gain control, noise suppression, and echo cancellation. Two phones measuring the same sound commonly differ by 5–10 dB. Calibration against a known reference removes most of the difference.

Browsers require explicit permission before any website can access your microphone — it is a privacy safeguard built into every modern browser. The meter needs that access to hear and measure the sound around you, and it only works while you allow it.

No. Audio is processed locally in your browser using the Web Audio API and is never recorded, stored, uploaded, or listened to. No network request is involved in measurement, and you can verify this by measuring with your device offline.

No. For everyday awareness, comparisons, and education, an online decibel meter is genuinely useful. For regulatory compliance, legal evidence, workplace assessments, or any measurement that will be challenged, you need a certified sound level meter meeting standards such as IEC 61672 and calibrated by a laboratory.

No. Phone and browser measurements are estimates, not certified measurements, and are not accepted for legal or regulatory compliance purposes. Use a calibrated instrument that meets the applicable standard (for example, IEC 61672) and have measurements conducted by qualified professionals.

The minimum shows the quietest sound captured during the session, the maximum shows the loudest peak, and the average reflects the typical level over time. Leq is the energy-equivalent level for the whole session and is the metric professionals use to assess noise exposure.

Sustained exposure at or above 85 dB can damage hearing over time. Levels above 90 dB are increasingly risky, and sounds above 120 dB can cause immediate damage. Protect your ears at concerts, workshops, and other loud places, and use the noise exposure guide to understand safe durations.