Be t Noi e Meter App : Compare Accurate Decibel Meter

Anyone who has ever tried to prove that their upstairs neighbor is breaking the noise ordinance knows the frustration. Your smartphone might actually be the tool you need. This guide compares the best noise meter apps for iPhone and Android, using peer-reviewed research and official CDC guidelines to separate the reliable tools from the ones that just look good on screen.

CDC NIOSH SLM app page published: February 16, 2024 ·
Decibel X availability: iOS App Store ·
Sound Meter & Noise Detector availability: Google Play ·
NIOSH SLM accuracy: ±2 dBA (CDC)

The pattern across these apps: only NIOSH SLM carries a government-published accuracy specification. The others rely on store-page claims or third-party tests that reveal significant variance.

What is the best noise meter app?

No single app wins in every scenario. The choice depends on your platform, your budget, and whether you need readings that hold up to scrutiny. The research points to different leaders for different use cases.

NIOSH SLM

The CDC-developed NIOSH Sound Level Meter app is the only free option with a published accuracy specification of ±2 dBA. It was tested in a reverberant chamber at the NIOSH acoustics laboratory and meets Type 2 requirements of IEC 61672:3 when used with a calibrated external microphone (CDC / NIOSH). The catch: it is available only on iOS.

“The NIOSH Sound Level Meter app measures workplace noise to determine if workers are exposed to hazardous noise.”

— CDC (NIOSH), official app page

Decibel X

Decibel X (also called dB X Pro) is available on both iOS and Android (EchoBarrier Blog). In the Murphy and King study of 100 phones, the iOS version of dB X Pro was the only app that underestimated the noise level in all test environments. The Android version read significantly below the professional sound level meter in the bus and Skytrain environments (Canadian Audiologist).

Decibel Pro

Decibel Pro is an iOS-only paid app that appears on recommendation lists from sites like Soundly.com. No peer-reviewed study validating its accuracy was found in the research. It offers a fuller feature set than many free apps, but the accuracy claims are unverified by independent testing.

Are noise meter apps accurate?

Accuracy varies by app, phone model, and environment. The Murphy and King study tested 100 phones across seven manufacturers — 18 Android and seven iOS models — and found that variations of 3 dB or greater from the professional sound level meter were common across all apps tested (Canadian Audiologist).

How accurate are smartphone microphones?

Smartphone built-in microphones are designed for voice calls, not precision acoustics. They can pick up sound levels reasonably well in mid-range frequencies, but low and high frequencies are often rolled off. The CDC notes that the NIOSH SLM app meets Type 2 requirements of IEC 61672:3 when paired with a calibrated external microphone — a clue that the built-in mic has limits for professional-grade measurement (CDC / NIOSH).

What does the research say?

The Canadian Audiologist study provides the most direct comparison available. Key findings: only the NIOSH app stayed within 3 dB of the professional meter across nearly all environments. All other apps — Decibel X (both platforms), AudioTools, SoundPrint — showed deviations of 3 dB or more in at least some settings. AudioTools measured significantly higher than the sound level meter in the nightclub and fitness class environments (Canadian Audiologist).

Can I measure noise with my phone?

Yes — but with caveats. Your phone’s built-in microphone is sufficient for basic awareness: is the room louder than a vacuum cleaner (~80 dB)? Quieter than a conversation (~60 dB)? For rough categorisation, any decent app will get you in the ballpark.

What do I need to use a noise meter app?

You need a smartphone with a working microphone and a noise meter app. That is it. For better accuracy, an external calibrated microphone can be connected via the headphone jack or Lightning/USB-C port. The CDC states that the NIOSH SLM app provides accurate measurement using any iOS device, but external microphones improve results to Type 2 standard (CDC / NIOSH).

Steps to measure noise

1. Choose your app — pick one from the comparison table above based on your platform and accuracy needs.
2. Hold the phone correctly — point the microphone (usually at the bottom of the phone) toward the noise source. Do not cover it with your hand.
3. Wait for a stable reading — let the app run for 10-15 seconds before recording the value. Noise fluctuates, so an average reading is more useful than a peak.
4. Log the data — take a screenshot or use the app’s logging feature. Note the time, location, and duration.
5. Compare to known levels — normal conversation is ~60 dB, a vacuum cleaner is ~80 dB, and sustained exposure above 85 dB can cause hearing damage.

Is there a free dB meter for iPhone?

Yes — the NIOSH SLM app is free and available on the iOS App Store. It is the only free noise meter app with a government-published accuracy specification. Decibel X also offers a free version with in-app purchases for additional features. SoundMeter X is a paid iOS app with advanced logging but no free tier.

Free vs paid apps

The free apps — NIOSH SLM, Decibel X free tier, SoundPrint — give you basic decibel readings and sometimes logging. Paid apps like Decibel Pro and SoundMeter X add features like frequency analysis, exportable reports, and calibration adjustments. The irony: the most accurate free app (NIOSH SLM) outperforms many paid options in peer-reviewed testing.

Features of free apps

Free apps typically display real-time decibel levels, show a simple graph, and may log readings. NIOSH SLM adds noise dose calculation based on occupational exposure limits. Decibel X free includes a basic meter with ads. SoundPrint focuses on crowd-sourced noise level mapping rather than personal measurement.

“If you’re on an iPhone, the NiOSH SPL app is by far the best of the bunch.”

— Reddit user, r/livesound

What is the best app to record noise from upstairs neighbors?

For documenting neighbor noise, you need an app that logs readings over time and exports data. The NIOSH SLM app can do this on iOS. For Android, Sound Meter & Noise Detector includes a graph feature that shows noise levels over time, though its accuracy has not been peer-reviewed.

How to use a noise meter app for neighbor noise

Position your phone in the room where the noise is loudest — typically near the ceiling or shared wall. Let the app run for several minutes to capture peak and average levels. Most ordinances set limits around 55-65 dB during nighttime hours depending on the jurisdiction. Your app data gives you a starting point for discussions with the landlord or local code enforcement.

Documenting noise levels

Screenshots alone may not hold up as evidence. For stronger documentation, use an app that logs timestamps and duration. Take multiple readings at different times. The important limitation from the research: apps can show you relative loudness, but the ±3 dB variance found in most apps means borderline cases are hard to call precisely (Canadian Audiologist).

Frequently Asked Questions

The pattern across all available data: one app — NIOSH SLM — carries institutional validation that the others lack. For anyone who needs a free, scientifically defensible noise reading on an iPhone, that app is the only real choice. Android users should treat any single reading with caution and cross-check across apps.