# Noise Decibel Meter vs KeepKnow

The clearest difference is in-app purchases: KeepKnow at none against Noise Decibel Meter's 1. KeepKnow also leads on update cadence (every 3 months vs every 8 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Noise Decibel Meter sells 1 in-app purchase, starting at $3.99 per month. KeepKnow asks for nothing beyond the download.

Noise Decibel Meter ships an update every 8 months, KeepKnow every 3 months. The most recent releases landed on September 29, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Noise Decibel Meter | KeepKnow |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 3 months** |
| Size | 29 MB | 48 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Packhorse Tech Co.,Ltd](https://appshunter.io/developer/1610710377) | [KeepKnow New Energy Limited](https://appshunter.io/developer/1893814746) |

## What reviewers say

### Noise Decibel Meter

[App page](https://appshunter.io/ios/app/noise-decibel-meter-db-meter/id6723885133)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 噪音分贝仪专业版 | $3.99 | per month |


### KeepKnow

[App page](https://appshunter.io/ios/app/keepknow/id6762320766)

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

**In-app purchases:** none


## Frequently asked questions

### Is Noise Decibel Meter free?

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

### Is KeepKnow free?

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

### Do Noise Decibel Meter or KeepKnow have ads?

Neither Noise Decibel Meter nor KeepKnow shows ads.

### Which is updated more often, Noise Decibel Meter or KeepKnow?

Noise Decibel Meter ships an update every 8 months, and KeepKnow every 3 months. Most recently, Noise Decibel Meter was updated on September 29, 2026 and KeepKnow on October 25, 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.*