Decibel X
An app that measures how loud it is around you in decibels.
What Decibel X does
Decibel X is one of the most popular decibel meter apps, with over 160,000 ratings on the App Store. It shows how loud your surroundings are in real time, keeps a history of readings, and works on iPhone, Apple Watch and Android. The basic meter is free; extras come with a membership or single add-ons.
If you searched for an app that measures decibels, this is a name you'll see a lot. Open it and you get a live decibel reading, plus graphs that show how the noise changes over time. The developer says readings come pre-calibrated, and you can trim the calibration yourself if you have a reference meter.
There's a lot under the hood: different frequency weightings, a spectrum analyzer, a history you can export, iCloud sync and themes. On iPhone you can glance at noise levels on your Apple Watch and save readings to the Health app. The Android version adds a noise dose meter based on NIOSH and OSHA standards and photo overlays for sharing a reading.
The free version shows ads. A membership covers everything for $1.99 a week, $5.99 a month or $49.99 a year, or you can buy single features like extra weightings or export. Keep in mind that any phone microphone has limits, so treat readings as a good guide rather than a certified measurement.
Alternatives to Decibel X
Who it's for
Skip it if: Legal or certified noise measurements.
Pricing
Free planFree to use with ads. On the US App Store, a membership costs $1.99 a week, $5.99 a month or $49.99 a year. You can also buy single add-ons: extra weightings for $1.99 or data export for $2.99. There's a short free trial of premium features.
Prices can vary by country. Checked 19 Oct 2026.
What people like
- Huge number of ratings and a high score
- Works on iPhone, Apple Watch and Android
- Free meter is useful on its own
- Lets you buy single features instead of a plan
Watch out for
- Ads in the free version
- Many extras need a membership
- Phone microphones limit accuracy
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Questions people ask
Is Decibel X free?
Yes, the basic meter is free with ads. Membership or add-ons cover extra features.
How accurate is Decibel X?
It's pre-calibrated and you can adjust it, but a phone microphone has limits. Use it as a guide, not a certified meter.
Does Decibel X work on Apple Watch?
Yes. You can see noise levels on your wrist, and it can save readings to the Health app.
Is Decibel X on Android?
Yes. It's on Google Play as Decibel X - Pro Sound Meter.