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Measure sound levels right now, in your browser. Allow microphone access below for live A-weighted (dBA) readings, OSHA exposure tracking, and frequency analysis. No audio leaves your device.
Measure sound levels in your browser
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Audio is analysed on your device. Nothing is recorded, stored, or uploaded.
Best for screening, comparison, and ongoing monitoring. Not a substitute for a calibrated Type 1 or Type 2 meter where compliance documentation is required — see how accurate this is and how it works.
A number on its own is hard to judge. The decibel scale is logarithmic, so a 10 dB rise is roughly a doubling of perceived loudness and a tenfold increase in sound intensity. That is why the gap between 60 and 70 dBA is a nuisance and the gap between 90 and 100 dBA is a hazard. Use this table to place whatever the meter is showing you.
| Level | Category | Typical sources | What it means |
|---|---|---|---|
| 0–30 dBA | Silent | Rustling leaves, a quiet bedroom at night, breathing | At or near the threshold of hearing. No risk at any duration. |
| 30–50 dBA | Quiet | Library, refrigerator hum, a whisper at one metre | Comfortable for sleep and concentration. The WHO night-noise guideline sits around 40 dB. |
| 50–70 dBA | Moderate | Normal conversation, dishwasher, office activity, light traffic | Normal daily life. Below roughly 70 dBA there is no known risk of hearing damage, even over 24 hours. |
| 70–85 dBA | Loud | Vacuum cleaner, busy street, hair dryer, restaurant at peak | Annoying and fatiguing over time. Risk begins to accumulate toward the top of this band. |
| 85–100 dBA | Harmful | Lawn mower, power tools, motorcycle, subway platform | OSHA's action level is 85 dBA. Hearing protection is warranted, and exposure time starts to matter a great deal. |
| 100–120 dBA | Dangerous | Chainsaw, nightclub, rock concert, jackhammer at close range | Damage can begin within minutes. Most phone microphones also start compressing in this range. |
| 120+ dBA | Immediate risk | Jet engine at 30 m, siren at close range, gunshot (impulse) | Pain threshold and above. Injury can occur from a single exposure with no warning. |
Hearing damage is a function of level and time together, not level alone. Two limits are in common use in the United States and they do not agree. NIOSH recommends 85 dBA for 8 hours with a 3 dB exchange rate, meaning safe time halves for every 3 dB increase — this follows the physics, since 3 dB is a doubling of sound energy. OSHA's enforceable standard permits 90 dBA for 8 hours with a more lenient 5 dB exchange rate. A workplace can therefore be legally compliant and still exceed what health researchers consider safe.
| Sound level | NIOSH limit (3 dB) | OSHA limit (5 dB) |
|---|---|---|
| 85 dBA | 8 hours | 16 hours |
| 88 dBA | 4 hours | 10 hours 33 min |
| 91 dBA | 2 hours | 6 hours 58 min |
| 94 dBA | 1 hour | 4 hours 36 min |
| 97 dBA | 30 minutes | 3 hours 2 min |
| 100 dBA | 15 minutes | 2 hours |
| 103 dBA | 7.5 minutes | 1 hour 19 min |
| 106 dBA | 3.75 minutes | 52 minutes |
| 112 dBA | 56 seconds | 23 minutes |
| 115 dBA | 28 seconds | 15 minutes |
Figures are computed from the NIOSH 3 dB and OSHA 5 dB exchange-rate formulas rather than transcribed from the abbreviated tables printed in each standard, so intermediate levels are included. OSHA caps enforceable exposure at 115 dBA for continuous noise. To turn a varying day into a single number, use the noise dose calculator.
DecibelPro reports sound pressure level in A-weighted decibels (dBA). A-weighting discounts very low and very high frequencies to approximate how the human ear actually perceives loudness, and it is the same weighting professional sound level meters use for workplace and environmental measurement. Every occupational limit you are likely to be held to — OSHA, NIOSH, and most municipal ordinances — is written in dBA, so an unweighted reading would not be comparable to them even if it were perfectly accurate.
Alongside the instantaneous level, the meter tracks the peak, running average, minimum and maximum for the session, and computes an 8-hour time-weighted average with a dose percentage against the OSHA action level and permissible exposure limit. The rolling waveform shows how the level moves over time, which is usually more informative than any single number, and the FFT frequency spectrum shows where in the audible band the energy actually sits — useful for identifying a specific offender like a compressor, a fan, or a fluorescent ballast.
Below roughly 70 dBA there is no known risk of hearing damage, regardless of how long the exposure lasts. Above that, risk accumulates with time. OSHA sets a permissible exposure limit of 90 dBA averaged over an 8-hour shift and an action level of 85 dBA, at which employers must implement a hearing conservation program including monitoring and audiometric testing. NIOSH recommends the stricter 85 dBA limit. Above 100 dBA damage can begin within minutes, and sounds above about 120 dBA can injure on a single exposure.
Noise-induced hearing loss is cumulative and permanent. It typically begins at 4 kHz — the region that carries the consonants that make speech intelligible — which is why the first symptom is often difficulty following a conversation in a busy room rather than a general sense that things are quieter. The damage is to hair cells in the cochlea, and those do not regenerate. Persistent tinnitus, or a temporary muffling of hearing after a loud event, is a warning that the exposure was enough to matter.
Hearing is not the only endpoint. The WHO and the European environmental noise literature link chronic exposure at far lower levels to sleep disruption, elevated stress hormones, and cardiovascular risk; the WHO night-noise guidance is framed around roughly 40 dB outside bedrooms. If you are measuring a bedroom or a neighbour dispute rather than a shop floor, those are the numbers that matter, and they are much lower than the occupational ones.
There is no special hardware involved. The same microphone your device uses for calls feeds a signal chain that mirrors what a handheld meter does internally.
The browser opens a microphone stream through the Web Audio API once you grant permission. Nothing is written to disk and nothing leaves the device.
A cascaded biquad filter applies the IEC 61672 A-weighting curve, attenuating low and very high frequencies to match the sensitivity of human hearing.
The weighted signal is converted to a root-mean-square amplitude over a short analysis window, then to a sound pressure level in decibels on a reference scale.
Levels update many times a second, feeding the gauge, the peak/average/min/max statistics, the rolling waveform, and the FFT frequency spectrum.
Most of the error in a browser measurement comes from how the device is held, not from the software. These steps cost nothing and remove the largest sources of it.
Measure where the person is, not where the phone happens to be resting. A device on a desk picks up structure-borne vibration and surface reflections that your ears do not experience.
A finger, a thick case, or a pocket over the port can cost 10 dB or more. Find the port on your device before you start.
A reflective wall within a metre or so can add several dB. Aim for at least a metre of clearance in the direction of the source.
Bluetooth headsets, webcams, and USB interfaces will be selected by the browser if they are active, and their response is usually far worse than the built-in mic. Turn them off before granting permission.
Real environments fluctuate constantly. The average over a minute describes a room; a single instantaneous number describes one moment, which is rarely what you want to know.
Breath noise directly on the microphone is loud and will dominate a quiet-room measurement entirely.
Screen a shop floor, plant, or job site before commissioning a formal survey. The meter tracks an 8-hour time-weighted average and dose percentage against OSHA's 85 dBA action level and 90 dBA permissible exposure limit, so you can see which areas and which shifts are the actual problem rather than guessing.
Workplace noise guide →Project the meter and let a class watch its own volume. Teachers use it to set a visible target for group work, to demonstrate the logarithmic decibel scale with a sound the students make themselves, and to check whether a room's background noise is undermining speech intelligibility for students at the back.
Classroom meter →Set a consistent monitoring level between sessions, check the noise floor of a room before recording, and use the frequency spectrum to find where an HVAC rumble or fixture hum is sitting. Repeatability matters more than absolute accuracy here, and a browser meter is repeatable on a given device.
Decibel chart →Document a pattern before making a complaint. Dated readings over several days establish when a noise happens and roughly how loud it is, which is often what an authority asks for first. Most municipal ordinances are written in dBA at a property line, so knowing the local limit tells you whether you have a case worth pursuing.
US noise ordinances →Comparing two of your own readings on the same device is good to roughly ±1–2 dB, because device error is largely a fixed offset that cancels out of the comparison. Absolute accuracy is a different question and depends on your hardware: a recent iPhone or iPad typically lands within a few dB, while Android phones and laptops vary much more widely because manufacturers stage microphone gain differently. The accuracy page gives the ranges by situation, with sources.
The honest limits are these. Microphone frequency response varies between devices and is not certified against any standard. Operating system automatic gain control can compress or shift readings without telling you. Most phone and laptop microphones clip somewhere around 100 to 105 dB, so a concert or a firing range will read lower than it is — if the number appears to plateau in a very loud place, you have found the hardware ceiling rather than the true level. And nothing here is traceable to a calibration certificate.
For OSHA documentation, enforcement, an insurance claim, or litigation, use a calibrated Type 1 or Type 2 sound level meter with a current calibration record, or engage an occupational hygienist. Compare the trade-offs in online versus hardware decibel meters, or see which instruments are worth buying in our sound level meter review. The right way to think about a browser reading is as the evidence that tells you whether paying for a real measurement is justified.
Interactive comparison of common sounds, from a whisper to a rocket launch
View chart →Work out an 8-hour TWA and dose percentage under OSHA and NIOSH rules
Calculate dose →The complete workplace noise safety and compliance guide
Read guide →Hardware meters tested, reviewed, and compared for 2026
Read review →Exposure limits, exchange rates, and health effects on this page are drawn from the following primary sources.
Full citation list on the references page. This site provides general information about sound measurement and is not medical advice.