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Free Decibel Meter

Decibel Meter

A free, private, browser-based sound level meter. Nothing is ever recorded or uploaded.

Turn on your microphone

This measures the sound around you in real time.

Audio is processed on your device only. Nothing is ever recorded, saved or uploaded.

Settings

Measurement

Weighting
Response

Microphone

Calibration

Default sensitivity

Uncalibrated estimate from your device microphone. Typical accuracy is within ±3–5 dB.

Saved sessions

Sessions are stored only on this device.

No saved sessions yet.

    Select 2 or 3 sessions to compare them.

    A decibel meter measures how loud the sound around you is, in decibels (dB) — the standard unit for sound pressure level. This free online decibel meter turns your phone, tablet or laptop's built-in microphone into a real-time sound level meter, right in your browser.

    Nothing you say or record is ever sent anywhere. Every calculation — the weighting filters, the averaging, the statistics — runs locally in your device, in JavaScript and a dedicated audio worklet. Close the tab and it is gone.

    How this online decibel meter works

    Once you allow microphone access, the tool requests your microphone's raw audio signal with the browser's automatic gain control, noise suppression and echo cancellation explicitly disabled — features designed for voice calls, not measurement, that would otherwise quietly distort the level you're trying to read.

    That raw signal is fed into an AudioWorklet, a dedicated audio-processing thread, which applies A-, C- or Z-frequency weighting (built from the same filter shapes defined in IEC 61672-1, the international standard for sound level meters) and computes a running root-mean-square level 100 times a second. The result is converted to decibels and shown with either Fast (125 ms) or Slow (1 s) time response, matching the two standard response speeds used by real sound level meters.

    How to use it

    1. Allow microphone access when your browser asks — this happens only after you tap "Start measuring," never automatically.
    2. Hold your device normally, or set it down near what you want to measure.
    3. Watch the live reading, or leave the tool running: Min, Max, Leq and Peak build up automatically over your whole session.
    4. Use Reset to start a fresh session without ending your microphone permission, or Stop to release the microphone entirely.
    5. Optionally calibrate against a trusted reference meter from the Settings panel, or switch between A/C/Z weighting and Fast/Slow response speed.

    How to read the readings

    dB(A) weighting shapes the measurement to match how the human ear perceives loudness at typical listening levels, and is what almost every noise regulation and hearing-safety guideline is written in — it is the default here. dB(C) weights low frequencies more heavily and is used for peak/impulse noise like machinery or gunfire. dB(Z) applies no weighting at all — a flat, unweighted measurement useful mainly for audio engineering.

    Min and Max are the lowest and highest readings seen since your last reset. Leq is the equivalent continuous level — a true energy average over the whole session, not a simple arithmetic mean, which is why a single loud spike can raise it more than a string of quiet moments lowers it. Peak captures the single loudest instant, unweighted by time response.

    Fast response reacts to changes within 125 milliseconds, closely tracking short bursts of sound. Slow response averages over a full second, smoothing out momentary spikes to show a steadier trend — useful for judging a room's general noise level rather than every passing sound.

    Decibel levels at a glance

    Every level below links to its own page with real-world examples, safe-exposure guidance and a mini meter you can use to check how your current surroundings compare.

    See the full decibel chart →

    How accurate is a phone or laptop decibel meter?

    Honestly: it's an estimate, not a calibrated measurement. Consumer microphones vary in sensitivity from one device to the next, and none of them ship pre-calibrated to a known sound-pressure reference the way a purpose-built, IEC 61672-1 compliant sound level meter does.

    With browser audio-processing features turned off — which this tool does automatically — a typical phone or laptop microphone reads within roughly ±3–5 dB of a calibrated reference in normal conditions. You can narrow that further: open Settings and enter a reading from a trusted reference meter taken at the same moment, in the same spot, and the tool will calculate and remember a calibration offset for that specific microphone.

    For anything requiring legal, regulatory or occupational-compliance accuracy, use a calibrated Class 1 or Class 2 sound level meter built to IEC 61672-1 or ANSI/ASA S1.4. This tool is built for everyday awareness: is my apartment too loud, is this concert dangerous for my ears, is my classroom too noisy right now.

    Safe noise levels and exposure time

    NIOSH's Recommended Exposure Limit (REL) is 85 dB(A) averaged over an 8-hour workday, using a 3 dB exchange rate — every 3 dB increase halves the safe exposure time, so 88 dB is only advised for 4 hours, 91 dB for 2, and so on. OSHA's legal Permissible Exposure Limit (PEL) is more permissive: 90 dB(A) over 8 hours, with a 5 dB exchange rate.

    For environmental noise rather than occupational exposure, WHO recommends outdoor night-time levels stay at or below 40 dB Lnight to protect sleep, and flags 70 dB as a general threshold above which community noise annoyance rises sharply. The Decibel Chart and Noise Dose Calculator on this site apply both the NIOSH and OSHA models to any level and duration you enter.

    What you can measure

    Everyday uses people find for a free decibel meter: checking whether a bedroom is quiet enough to sleep in, settling a dispute about how loud a neighbor's noise really is, sanity-checking an office or open-plan workspace, monitoring a classroom with the Noise Monitor's traffic-light classroom mode, judging whether a concert or a pair of headphones is at a genuinely risky volume, or comparing appliances like blenders, hair dryers and vacuum cleaners before you buy one.

    Embed this meter

    Add a free, live decibel meter to your own site or blog post — no account or API key required. The Embed page generates a ready-to-paste iframe snippet with microphone permission scoped to your domain. Get the embed code →

    Privacy: audio never leaves your device

    This tool never records, saves or transmits your audio. Every measurement is computed locally in your browser and discarded the moment you close the tab, reset the session, or navigate away. See the Privacy page for the full detail on what, if anything, is stored (only your own local calibration offset and theme preference, on your own device). Read the Privacy page →

    Frequently asked questions

    What is a decibel meter?
    A decibel meter (sound level meter) measures how loud a sound is, in decibels (dB) — the standard logarithmic unit for sound pressure level. This free online decibel meter uses your device's microphone to estimate dB(A) sound levels in real time, entirely inside your browser.
    Can I measure dB(A) with my phone?
    Yes. Your phone or laptop's built-in microphone can estimate dB(A) sound levels through a browser tool like this one. It won't match a calibrated Class 1 or 2 sound level meter built to IEC 61672-1, but with the browser's automatic gain control turned off, it gives a genuinely useful real-time estimate, typically accurate within about ±3–5 dB.
    How do I read a decibel meter?
    The large number is the current dB(A) level. Min, Max, Leq and Peak summarize your session: Min and Max are the lowest and highest readings seen, Leq is the true energy-averaged level over the whole session, and Peak is the single loudest instant captured. "Fast" response reacts within 125 ms; "Slow" smooths readings over a full second.
    Which decibel meter is the best?
    It depends on the job. A calibrated Class 1 sound level meter built to IEC 61672-1 is required for legal, regulatory or occupational-safety measurements. For everyday checks — is my room too loud, is this safe for my ears — a free browser-based decibel meter needs no hardware purchase and is accurate enough to answer that.
    Which decibel meter is free?
    This one. Free Decibel Meter runs entirely in your browser with no account, no app download and no audio ever leaving your device. There is no paywalled tier for readings, CSV/PNG exports, session history or the spectrum analyzer — every feature is free.
    What does a decibel meter cost in India?
    A basic handheld digital sound level meter in India typically costs ₹800–₹3,000; calibrated Class 2 professional meters used for workplace compliance run ₹15,000 and up. A browser-based decibel meter like this one is free and needs no hardware purchase for everyday noise checks.
    What is a normal decibel range?
    Everyday indoor life mostly falls between 40 and 70 dB — a quiet room reads around 40 dB, normal conversation around 60 dB. Outdoor city environments commonly run 70–85 dB. NIOSH sets 85 dB as the level above which daily exposure starts to carry real hearing-risk.
    What is the loudest safe decibel level?
    For an 8-hour workday, NIOSH's Recommended Exposure Limit is 85 dB; OSHA's legal Permissible Exposure Limit is 90 dB. Above either threshold, safe exposure time drops quickly — roughly halving every 3 dB under NIOSH's exchange-rate model, and every 5 dB under OSHA's.
    What is 1 dB of sound?
    One decibel is the smallest change in sound pressure level most people can just barely detect under controlled, quiet conditions. On its own, 1 dB sits close to the threshold of human hearing and is far quieter than any typical everyday sound.
    Can a human hear 1 dB?
    Barely, and only under ideal, silent conditions — 1 dB sits right at the edge of the average threshold of human hearing, which is defined as 0 dB SPL. In any real room with normal background noise, a 1 dB sound is inaudible.
    Is 1 dB twice as loud?
    No. Because decibels are a logarithmic scale, it takes roughly a 10 dB increase for a sound to be perceived by most people as "twice as loud," and about a 3 dB increase for the sound's actual acoustic energy to double. A 1 dB change is only just perceptible.
    What is the 3 decibel rule?
    The 3 dB exchange rate, used by NIOSH and most of the world outside the United States, means every 3 dB increase doubles the sound energy — and halves the safe daily exposure time. It is why 88 dB is only allowed for about 4 hours where 85 dB is allowed for 8.
    Is zero decibels possible?
    0 dB SPL is defined as the average threshold of human hearing, not "no sound" — sound pressure below that level still physically exists, most people simply cannot hear it. True silence, zero sound pressure, essentially never occurs outside a lab.
    What is a normal hearing range?
    Healthy human hearing typically spans from about 0 dB, the threshold of hearing, up to roughly 120–130 dB, the threshold of discomfort and pain, across a frequency range of about 20 Hz to 20,000 Hz — though sensitivity to high frequencies narrows with age.

    Sources