# Unit Converter Engineering Pro vs HydroniCalc

The clearest difference is iOS requirement: Unit Converter Engineering Pro at 13.0 against HydroniCalc's 17.0. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Unit Converter Engineering Pro sells 2 in-app purchases, starting at $5.99 per 7 days and HydroniCalc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

## The numbers

| Metric | Unit Converter Engineering Pro | HydroniCalc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/unit-converter-engineering-pro/id6757166485/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Weekly | — |
| Monetization | Free with in-app purchases | — |
| Size | 77 MB | 7 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Kaiguri Tech](https://appshunter.io/developer/1864995084) | [Eric Chmara](https://appshunter.io/developer/1892404568) |

## What reviewers say

### Unit Converter Engineering Pro

[App page](https://appshunter.io/ios/app/unit-converter-engineering-pro/id6757166485)

This app provides precise unit conversions for engineers, scientists, and students. It supports over 100 units across 35 categories, including scientific notation and 9-digit decimal precision. The tool works offline and adheres to SI, NIST, and ISO standards.

**Highlights:** Over 100 units in 35+ categories, Scientific notation support, 9-digit decimal precision, SI, NIST, ISO compliant, Offline functionality, Specialized units included

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 3-Day Trial | $5.99 | per 7 days |
| Yearly Plan | $19.99 | per year |


### HydroniCalc

[App page](https://appshunter.io/ios/app/hydronicalc/id6796810526)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Calculators | $12.99 | one-time |


## Frequently asked questions

### Is Unit Converter Engineering Pro free?

Unit Converter Engineering Pro is free to download, with in-app purchases available.

### Is HydroniCalc free?

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

### Do Unit Converter Engineering Pro or HydroniCalc have ads?

Neither Unit Converter Engineering Pro nor HydroniCalc shows ads.

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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.*