What actually matters in a sound level meter app, and what's just noise.
There are dozens of sound meter apps on the App Store. Most of them are fine. Some of them are great. A few are terrible. Here's how to tell the difference.
Before we get into specifics, let's establish something: every decibel meter app on your iPhone is using the same microphone hardware. The differences between apps come down to how they process the audio signal, how they display the results, what additional features they offer, and how much they charge you for the privilege.
With that in mind, here are the things that actually matter.
Accuracy within reason. No phone app will match a calibrated professional meter. But a good sound meter app should give you readings that are consistently in the right ballpark. If your quiet room reads 40 dB and a loud conversation reads 65 dB, those numbers should be roughly proportional to reality. Consistency matters more than absolute accuracy here. You want an app that reliably reflects changes in sound level, even if the absolute number is a few dB off from a professional meter.
Readability. This is more important than most people realize. A decibel meter is something you glance at. You're not studying it like a textbook. The display needs to communicate the current sound level instantly, at a glance, in any lighting condition. A number on a screen works. A well designed analog meter works better because your brain processes the needle position and movement faster than it reads and interprets a changing number.
Visual design. You're going to be looking at this app. It should look good. Sound meter apps that look like they were designed in a basement in 2009 still work, technically, but using them feels like operating industrial software. The best sound level meter apps treat the interface as a feature, not an afterthought.
Useful features, not feature bloat. Live charting over time? Useful. Peak detection? Useful. A/C frequency weighting toggles, FFT spectrum analysis, and 47 export options? That's great if you're an acoustic engineer, but if you just want to check how loud your apartment is, it's clutter. The best apps give you what you need and stay out of the way.
Price. Some very good sound meter apps are paid. That's fair. But the paid ones typically charge between $3 and $15, and some of the most popular ones run on subscription models. For an app category where the underlying measurement capability comes from your phone's hardware, paying a monthly subscription feels steep. Free apps with no catches are rare in this category, but they exist.
A fair look at what's available before we talk about our own app.
The App Store has a solid range of sound meter apps at this point. Apple's own Health app on iPhone includes a noise level monitoring feature, though it's designed more for headphone exposure tracking than active sound measurement. It runs in the background and logs environmental sound levels, which is useful for awareness but not the same as a dedicated measurement tool you can actively monitor.
NIOSH (the National Institute for Occupational Safety and Health) released a Sound Level Meter app that was well regarded for its accuracy and straightforward design. Several third party apps like dB Meter, Decibel X, and Sound Meter have been around for years and offer various combinations of features, calibration options, and frequency weighting.
The paid apps in this space tend to offer more technical features: A and C weighting, data export, calibration against reference levels, and detailed logging. If you're doing semi professional acoustic work and need those capabilities, a paid app with good reviews is worth considering.
The free apps tend to be more basic, and many of them support themselves with ads. Some display a banner ad during measurement, which is exactly as annoying as it sounds when you're trying to read a sound level. Others gate features behind in app purchases, so the free version is really just a demo.
And then there's the design question. Most sound meter apps look clinical. They show a number, maybe a bar graph, maybe a chart. They're functional but utilitarian. The display is information, not experience. That's fine if all you care about is the number. But if you want something you'd actually enjoy using and looking at, the options thin out considerably.
We built Decibels because we wanted a sound meter app that we'd actually want to use. Here's what that means in practice.
The VU meter is the whole point. Classic VU meters from the golden age of audio are beautiful objects. The cream colored face, the precise scale markings, the way the needle swings with momentum and settles back naturally. They communicate information through movement and position in a way that a bouncing digital number simply cannot. When you watch a VU meter, you get an intuitive, almost physical sense of sound intensity. We recreated that experience digitally, with carefully tuned needle ballistics that match how real analog meters behave. Fast attack for transients, smooth decay for the release. It looks gorgeous and it communicates sound levels more effectively than a number on a screen.
Live charting shows you the story. A single dB reading is a snapshot. A chart is a narrative. Decibels continuously plots your sound levels over time on a scrolling chart, so you can see patterns, trends, and anomalies. When the HVAC cycles on, you see it. When traffic picks up outside, you see it. When your neighbor starts their weekly drum circle, you see it spike. The chart turns raw numbers into something you can actually analyze and understand.
Peak detection catches what you miss. You can't stare at a meter all day. The peak indicator remembers the loudest moment so you don't have to. Set it down, come back later, and see the highest level recorded. This is especially useful for environmental monitoring where you want to know if there are occasional loud spikes even when the average level seems fine.
Adaptive layout because people hold their phones differently. Decibels works on iPhone and iPad, in portrait and landscape. The interface rearranges itself automatically. On an iPad in landscape, you get a spacious view with the meter and chart side by side. On an iPhone in portrait, it stacks them efficiently. You never have to rotate your device or squint at a layout that wasn't designed for your screen orientation.
Decibels is free. Not "free with ads." Not "free with a premium upgrade." Free.
There's no ad banner obscuring half the meter. There's no subscription wall that activates after three days. There's no in app purchase to unlock the chart feature. You download the app, you get the complete app, and you never pay anything.
We're a small studio that builds apps because we enjoy building them. Decibels exists because we wanted a sound meter that looked as good as the readings it provides. We didn't build it to be a revenue stream, so there's nothing to monetize. You get the whole thing for nothing.
In a category where some apps charge $5 to $15, and others run on $2 to $4 per month subscriptions, free with no catches is unusual. But it shouldn't be. The measurement capability comes from your phone's hardware. The app should add value through design and thoughtful features, and it shouldn't cost you a monthly fee to access the microphone you already own.
We'd rather be upfront about the limitations than have you discover them after downloading.
It's not a calibrated instrument. Decibels uses your iPhone or iPad's built in microphone, which is not a calibrated measurement transducer. Readings are estimates. They're useful estimates, they're consistent estimates, but they're not certified measurements. If you need readings that would hold up in a legal dispute, a workplace safety audit, or a scientific study, you need professional equipment.
It doesn't do frequency weighting. Professional sound level meters offer A weighting, C weighting, and sometimes Z weighting to account for how human ears perceive different frequencies. Decibels measures overall sound level without frequency weighting adjustments. For general reference use, this is perfectly fine. For technical acoustic analysis, it's a limitation.
It doesn't export data. The live chart is great for real time monitoring, but there's no data logging or CSV export feature. You can see your sound level history on screen while the app is open, but it's not recording that data to a file for later analysis. If you need logged data over time, some of the paid sound meter apps offer that capability.
It doesn't replace professional tools. This applies to every phone based sound meter, not just Decibels. For OSHA compliance, environmental impact assessments, audiological testing, or any application where measurement accuracy has legal or safety implications, use calibrated professional equipment. Decibels is a reference tool for everyday curiosity and general awareness, and it's very good at that.
If you want a decibel meter app that works well, looks great, and costs nothing, Decibels is hard to beat.
The vintage VU meter design isn't just aesthetic indulgence. Analog meter movement is genuinely more readable than a bouncing number, and the crafted needle ballistics make monitoring sound levels a pleasure instead of a chore. Add live charting, peak detection, and an adaptive layout that works on every device and orientation, and you've got a complete sound level meter that you'll actually enjoy using.
It's not trying to be a professional acoustic analysis tool. It's a beautifully designed, thoughtfully built sound meter for people who want to understand the noise around them. And it's completely free with no ads and no subscriptions.
If you need advanced features like frequency weighting, data export, or calibration profiles, one of the paid apps in the category might be a better fit for your specific needs. But if you want a sound level meter that does the fundamentals really well and looks gorgeous doing it, give Decibels a try.
The sound meter app that's actually nice to use. Free on the App Store.
