# dB Noise Meter vs O

The clearest difference is in-app purchases: O at none against dB Noise Meter's 5. O also leads on ads (none vs shown) and update cadence (every 4 days vs every 2 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. dB Noise Meter sells 5 in-app purchases, starting at $6.99 per 7 days. O asks for nothing beyond the download.

dB Noise Meter ships an update every 2 months, O every 4 days. The most recent releases landed on October 14, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | dB Noise Meter | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.8 (122 ratings)](https://appshunter.io/ios/app/db-noise-meter/id1590850487/reviews)** | — |
| Number of ratings | **122** | — |
| Positive reviews | 15.4% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 49 MB | 57 MB |
| Requires iOS | 16.6 | **16.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | +4 | 4+ |
| Developer | [Petr Polasek](https://appshunter.io/developer/1613323784) | [PUFin ID A/S](https://appshunter.io/developer/1614643757) |

## What reviewers say

### dB Noise Meter

[App page](https://appshunter.io/ios/app/db-noise-meter/id1590850487)

Measure ambient noise levels in decibels (dB) using your phone's microphone. Track real-time noise, identify loud appliances, and monitor your exposure to potentially harmful sound levels.

**Highlights:** Real-time decibel measurement, Noise level tracking, Appliance noise testing, Save noise measurements, Display min/max/avg dB

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium 1 week | $6.99 | per 7 days |
| Premium 1 Month | $9.99 | per month |
| Premium 3 Months | $17.99 | per 3 months |
| Premium 6 Months | $19.99 | per 6 months |
| Premium 1 Year | $29.99 | per year |


### O

[App page](https://appshunter.io/ios/app/o-key-authenticator/id6776659466)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is dB Noise Meter free?

dB Noise Meter is free to download, with in-app purchases available.

### Is O free?

O is free to download, with no in-app purchases.

### Do dB Noise Meter or O have ads?

dB Noise Meter shows ads; O does not.

### Which is updated more often, dB Noise Meter or O?

dB Noise Meter ships an update every 2 months, and O every 4 days. Most recently, dB Noise Meter was updated on October 14, 2026 and O on October 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*