iPhone Decibel Meter – Free Online, No Download, Use in Browser

Does iPhone have a decibel meter built in?

Not as a number you can read. iOS has noise alerts on Apple Watch and hearing data in Health, but no system-wide live dB readout on iPhone. That gap is exactly what this free online decibel meter fills: Safari grants microphone access to the page, the page computes RMS → dB → A/C/Z weighting → Fast/Slow → Leq locally, and you see current, minimum, average and maximum estimated decibels with a live graph.

No download: how the web tool works on iPhone

There is nothing to download and nothing to install. This iPhone decibel meter is a web page: Safari asks for microphone permission, the page processes sound locally with the Web Audio API, and shows current, minimum, average and maximum estimated decibels with a live graph. Close the tab and it is gone — no storage used, no updates to manage. That is why it is the easiest option for a quick check on your own iPhone or someone else's.

Browser or decibel meter app on iPhone?

For one-off checks the browser wins: no App Store install, no account, always current, microphone permission scoped to the site, and audio that never leaves the device — see privacy. Install a native decibel meter app only if you need offline-first use or background logging. Accuracy is the same story either way: uncalibrated phone mics are estimates.

How accurate is an iPhone decibel meter?

Treat it as rounded to a few dB. iPhones read consistently per model but offset against other devices because Safari tends to keep system gain processing active. Practical limits: below ~30 dBA the mic noise floor reads too high, above ~95–100 dBA it clips, and deep bass is under-reported. Ignore decimals, compare 30–60 second Leq values, and do one calibration against a known reference. Full background in accuracy and limitations.

How to get the best iPhone reading

• Find the bottom-edge mic hole; remove case coverage and avoid holding it shut.
• Measure at ear height where people sit, mic pointed at the source.
• Stay silent, hold still, note distance with every reading.
• Use A-weighting + Slow for everyday comparison; C/Z for bass-heavy peaks — see dB vs dBA.
• Run 30–60 seconds and use Leq, per how measurement works.

Safari workflow from tap to reading

Stay in current Safari over HTTPS and open this page. Tap Start, Allow the microphone once — Safari remembers per origin — and hold the bottom-edge mic hole toward the source at ear height with the case clear. The page captures mono audio and asks for echo cancellation, noise suppression and automatic gain off; Safari often keeps some processing on, shown in the device panel. Run 30 to 60 seconds on Slow response, then read Leq across current, minimum, average, maximum and duration on the 240-point graph. The readout is a labelled estimate (weighted dBFS plus nominal +100 dB offset, raw dBFS in Digital Diagnostics); "--" means idle, never invented. Audio never reaches your speakers, with no download and no account.

Keep iPhone sessions and offsets straight

Safari keeps up to 20 sessions locally; CSV and JSON exports include dB values only after calibration. Calibrate against a stable known reference at the same spot and redo after a case change, new iPhone or major update. Never borrow another handset's offset — 5 to 10 dB spreads are normal. Fast at 125 ms suits claps, Slow at 1 second suits rooms — see calibration and background noise test.

When iPhone is not enough

An iPhone is never evidence. Noise complaints, workplace assessments and legal disputes need a calibrated Class 1 or Class 2 meter — see validation and disclaimer. For exposure context continue with noise exposure, the decibel chart, and the phone decibel meter guide for Android differences.

iPhone decibel meter FAQ

Open the online decibel meter → · All FAQs → · iPhone mic troubleshooting →

Use it in your language

This web tool needs no download in any language — open the matching homepage and tap Start. Each page links to its own language meter:

• Deutsch: Dezibel messen mit dem Handy – kostenlos online ohne App → · Deutsches Messgerät öffnen →
• 日本語: 騒音計アプリ・デシベル計測 – スマホで無料測定 → · 日本のメーターを開く →