Decibel Sound Meter: measure noise on your iPhone and iPad

What can you do with it?

Measure and record

The Meter tab starts reading the moment you allow the microphone — no setup screen, no tutorial to click through. It shows the current level in whole decibels, a peak held for two seconds, a coloured gauge and a plain word such as Conversational or Very Loud.

Tap Start Recording to track MIN, AVG and MAX with a chart of the last 60 seconds. Saved sessions go to History with a note, tags and, if you allow it, the place where you measured.

Estimate your daily noise dose

The Exposure tab adds up every sample against the NIOSH REL (85 dBA, 3 dB exchange rate) or the OSHA PEL (90 dBA, 5 dB exchange rate). You get the Dose as a percentage, the Projected 8 h dose, the TWA (8 h) and the Time left at current level. The whole tab is free.

Keep a record and share it

A saved session can become a PDF report, a CSV file, an image card or a text summary. The Video tab films a clip with the live dB level burned into the picture, and the Map tab places recordings that have a location on a noise map.

Quick start

1. Open the app and allow the microphone. The Meter tab starts reading straight away.
2. Hold the phone still, microphone uncovered, and keep your own voice out of it.
3. Tap Start Recording and let it run for 30 to 60 seconds so the average settles.
4. Tap Stop Recording, then Stop & Save. The session appears in History with its minimum, average and maximum.
5. If you need the absolute number, match a reference meter once with the Calibration row in the Exposure tab.

What is free and what Premium adds

The app is free to download. The meter, recording, history, all calibration controls, the full Exposure tab with CSV export of exposure sessions, the noise-level reference, alerts at 85 dB and 7 days of statistics cost nothing. The free version shows ads, and a few extras can be unlocked one at a time by watching an ad.

Premium, sold as a subscription or, where offered, a one-time Lifetime purchase, removes all ads. It adds unlimited PDF, CSV and image exports, the Noise Map, Compare Sessions, the Daily Noise Dose screen, 365 days of statistics, a custom alert threshold from 40 to 120 dB, Background Monitoring, videos up to 10 minutes with a 1080p option and no watermark and five extra colour themes.

Privacy, offline use and permissions

• No account. Recordings, exposure sessions and settings stay on the device, with no cloud sync.
• The meter turns sound into numbers in memory and does not save audio. Only the Video tab stores sound, inside the clip you record.
• Measuring, the Exposure tab, calibration and history work with no connection. You need one for ads (including an ad that unlocks a single export), for purchases and for turning a recording's coordinates into a place name.
• Camera: used by the Video tab alone. Location: optional, attached to recordings. Ad tracking: you can refuse it and the meter works exactly the same.

Limits, and who it is not for

• A phone microphone is not a Class 1 or Class 2 sound level meter or a personal dosimeter, and results vary between phone models.
• Only A-weighting and Fast response: no C or Z weighting, no Slow or Impulse response, no octave or frequency analysis.
• Very loud bangs such as fireworks clip and read low; readings stay between 0 and 140 dB.
• It cannot measure the level inside headphones or earbuds.
• Recordings are a personal log, not legal evidence or a workplace record, and the PDF report is in English.
• iPhone and iPad only, iOS 17 or later. There is no Apple Watch, Mac or Android version and no widget.