--- title: "Sound Level Meter Online: Live Decibels | City Hum Daily" description: "Free online sound level meter: live microphone level in dBFS or dB with your own calibration, A/C weighting, peak, Leq, min and history. Nothing recorded." url: https://cityhumdaily.buzz/ --- Live microphone · uncalibrated # Sound level meter Press Start and the meter reads your microphone in real time. Readings are in dBFS until you add your own calibration offset. No audio is recorded or sent anywhere. ## How to read the meter The big number is the current level. With no calibration it is in **dBFS**, decibels below the loudest signal your microphone input can carry, so it is always negative: −20 is loud, −70 is quiet. That scale is honest but it is not the dB you see in noise rules, because every phone and laptop microphone, and the processing behind it, has a different sensitivity. To get an **estimate in dB**, add a calibration offset. The best way is to stand next to a real sound level meter, play a steady sound such as pink noise or a fan, type the real meter's reading as the reference level and press *Set offset from current reading*. The offset is kept in this browser for next time. Treat the result as an estimate within a few decibels at best, and only for that device and browser. **A-weighting** follows how the ear hears moderate sounds and is what workplace and hearing guidance uses (dBA). **C** is nearly flat and **Z** applies no weighting. **Fast** and **Slow** are the 125 ms and 1 s time responses of IEC 61672-1. **Peak** is the highest reading, **Average** is the energy average (Leq), and the bars under the number split the sound into octave bands from 31 Hz to 16 kHz. Browsers cannot always switch off echo cancellation, noise suppression or automatic gain, and small microphones lose the lowest and loudest sounds. Use the meter to compare places and times, not to prove compliance. ## More noise tools - [Noise exposure calculator](https://cityhumdaily.buzz/noise-exposure-calculator/): Allowed time per level under NIOSH and OSHA, and the daily dose and TWA from several exposures. Check a workday - [Decibel calculator](https://cityhumdaily.buzz/decibel-calculator/): Add, subtract and average sound levels the logarithmic way, and work out level over distance. Do the dB maths - [Sound level chart](https://cityhumdaily.buzz/sound-level-chart/): Typical levels of everyday sounds from WHO, NIDCD and NIOSH, with hearing-protector estimates. Compare sounds - [Tone generator](https://cityhumdaily.buzz/tone-generator/): Sine, square, triangle and sawtooth tones from 20 Hz to 20 kHz, sweeps and WAV downloads. Play a tone ## Recommended Two free tools from outside the noise world that help when you are shopping for earplugs, booking gigs or trying apps you found online. Temporary email ### CleanTempMail Earplug shops, ticket sites and audio app downloads often want an email address before they hand over a discount code or a download link. CleanTempMail gives you an instant disposable inbox with no sign-up, and its messages delete themselves after three days, so the follow-up newsletters stay out of your real inbox. [Open a temporary inbox](https://cleantempmail.com/) Disposable browser ### WebTraceCheck Sent a link to a "free decibel app" or a ticket reseller you have never heard of? WebTraceCheck opens it in a cloud browser on an isolated Linux desktop that is deleted after each session, so you can look the site over without trusting it on your own device. There is free daily time and nothing to install. [Try the cloud browser](https://webtracecheck.com/) ## Questions **Is a phone or laptop sound meter accurate?** Not without calibration, and only roughly with it. Built-in microphones differ by tens of decibels in sensitivity, many roll off below about 100 Hz, and some limit loud sounds. With an offset set against a real meter, readings of steady sounds are often close, but this page is not a calibrated instrument and cannot replace a Class 1 or Class 2 meter. **Why are the readings negative?** Without calibration the meter shows dBFS, measured down from the loudest signal the microphone input can carry, which is 0 dBFS. A quiet room might read around −70 dBFS and a shout near the phone −20 dBFS. Add a calibration offset to turn these into estimated dB. **Is my audio recorded?** No. The browser hands the microphone signal to the page, which measures it a few times a second and throws each block away. Only the numbers stay in memory, and they are gone when you close the tab unless you download the CSV yourself. **Which sound levels are risky?** NIDCD says sounds at or below 70 dBA are unlikely to cause hearing loss, while long or repeated exposure at 85 dBA or more can. How long you can stay at a given level is worked out in the noise exposure calculator. This site gives no medical advice; see an audiologist about ringing ears or hearing changes. ## Sources 1. IEC 61672-1:2013, *Electroacoustics – Sound level meters – Part 1: Specifications* (A and C frequency weightings, Fast and Slow time weightings). 2. AES17, *AES standard method for digital audio engineering – Measurement of digital audio equipment* (full scale defined by a sine wave, so a full-scale sine reads 0 dBFS). 3. National Institute on Deafness and Other Communication Disorders, [Noise-Induced Hearing Loss](https://www.nidcd.nih.gov/health/noise-induced-hearing-loss).