# LudyMeter vs 通达T20

The clearest difference is in-app purchases: 通达T20 at none against LudyMeter's 2. 通达T20 also leads on update cadence (monthly vs every 6 months) and iOS requirement (15.1 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. LudyMeter sells 2 one-off in-app purchases. 通达T20 asks for nothing beyond the download.

LudyMeter ships an update every 6 months, 通达T20 monthly. Both last shipped on October 28, 2026.

## The numbers

| Metric | LudyMeter | 通达T20 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 6 months | **Monthly** |
| Size | 6 MB | 73 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Ludy Ankas, LLC](https://appshunter.io/developer/1839727404) | [北京通达信科科技有限公司](https://appshunter.io/developer/1018115125) |

## What reviewers say

### LudyMeter

[App page](https://appshunter.io/ios/app/ludymeter-sound-level-meter/id6760686850)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| LudyMeter Pro | $14.99 | one-time |
| LudyMeter Safety | $49.99 | one-time |


### 通达T20

[App page](https://appshunter.io/ios/app/t20/id6784624086)

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

**In-app purchases:** none


## Frequently asked questions

### Is LudyMeter free?

LudyMeter is free to download, with in-app purchases available.

### Is 通达T20 free?

通达T20 is free to download, with no in-app purchases.

### Do LudyMeter or 通达T20 have ads?

Neither LudyMeter nor 通达T20 shows ads.

### Which is updated more often, LudyMeter or 通达T20?

LudyMeter ships an update every 6 months, and 通达T20 monthly. Most recently, LudyMeter was updated on October 28, 2026 and 通达T20 on October 28, 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.*