# LSI Calculator vs testo Smart

The clearest difference is review sentiment: LSI Calculator at 100% against testo Smart's 16%. LSI Calculator also leads on rating (4.4 vs 2.7) and in-app purchases (none vs 5). testo Smart's advantage is ratings volume (170 vs 5). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. testo Smart sells 5 in-app purchases, starting at $6.99 per month. LSI Calculator asks for nothing beyond the download.

LSI Calculator holds the better App Store score, 4.4 against 2.7. That said, the two scores are not equally well evidenced: testo Smart has 170 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 100% of LSI Calculator's written reviews are positive against 16% of testo Smart's.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on October 5, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | LSI Calculator | testo Smart |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (5 ratings)](https://appshunter.io/ios/app/lsi-calculator/id1233049990/reviews)** | [2.7 (170 ratings)](https://appshunter.io/ios/app/testo-smart/id1482139629/reviews) |
| Number of ratings | 5 | **170** |
| Positive reviews | **100.0% of reviews** | 16.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 52 MB | 195 MB |
| Requires iOS | **11.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [Pure Planet Science & Technology, Inc.](https://appshunter.io/developer/1234693265) | [Testo SE & Co. KGaA](https://appshunter.io/developer/966489178) |

## What reviewers say

### LSI Calculator

[App page](https://appshunter.io/ios/app/lsi-calculator/id1233049990)

This app provides tools and educational resources to help users manage water systems, focusing on eco-friendly treatments for pools and spas. It aims to make water maintenance accessible to everyone, regardless of their experience level.

**Highlights:** Water science education, Pool and spa water management, Eco-friendly treatment guidance, NSF/ANSI Certified product information, Tools for water system management

**Features:** macOS Compatibility

**In-app purchases:** none


### testo Smart

[App page](https://appshunter.io/ios/app/testo-smart/id1482139629)

This app supports measurements for refrigeration, HVAC, and heating systems. It also aids in food safety, frying oil quality, and indoor climate monitoring. Quickly interpret data, create digital reports with photos, and send them via email.

**Highlights:** All-in-one system measurements, Graphical display of measured values, Digital PDF/CSV measurement reports, Email report sharing, Leak test analysis, Automatic refrigerant charging, Indoor air quality monitoring

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

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Multi-site measurement | $6.99 | per month |
| Air balancing | $9.99 | per month |
| Multi-site measurement | $69.90 | per year |
| Air balancing | $99.90 | per year |
| Logging digital manifold | $44.99 | one-time |

**What reviewers like**

- 👍 Good app with some features
- 🚀 Great product
- 🚀 Useful app for measurements

**What reviewers complain about**

- 🐛 App won't connect
- 🐛 Connectivity issues
- 🐛 Unreliable connection
- 🐛 Forced updates
- 🐛 Laggy and unresponsive UI

**Reported bugs**

- App won't connect to devices
- Compatibility issues with newer iOS versions
- Frequent crashes and freezes
- Inability to save favorite refrigerants
- Measurement data not displaying properly

**Requested features**

- Add option to toggle Bluetooth discovery
- Improve Bluetooth range
- Add ability to customize colors and graphs
- Improve data export functionality
- Add option to name sensors


## Frequently asked questions

### Is LSI Calculator free?

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

### Is testo Smart free?

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

### Which has better reviews, LSI Calculator or testo Smart?

LSI Calculator is rated higher. LSI Calculator averages 4.4 out of 5 from 5 ratings, while testo Smart averages 2.7 from 170 ratings.

### Do LSI Calculator or testo Smart have ads?

Neither LSI Calculator nor testo Smart shows ads.

### Which is updated more often, LSI Calculator or testo Smart?

LSI Calculator ships an update every 2 months, and testo Smart every 2 months. Most recently, LSI Calculator was updated on October 5, 2026 and testo Smart 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.*