# Units Converter for Engineers vs PDF OCR

The clearest difference is review sentiment: PDF OCR at 100% against Units Converter for Engineers's 50%. PDF OCR also leads on rating (4.4 vs 3.0) and monetization model (free vs free with in-app purchases). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Units Converter for Engineers sells 2 one-off in-app purchases and PDF OCR sells 3 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

PDF OCR holds the better App Store score, 4.4 against 3.0. Both are backed by a comparable volume of ratings — 2 and 7 respectively. Written reviews point the same way: 50% of Units Converter for Engineers's written reviews are positive against 100% of PDF OCR's.

Units Converter for Engineers ships an update every 5 weeks, PDF OCR every 3 weeks. The most recent releases landed on September 19, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Units Converter for Engineers | PDF OCR |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.0 (2 ratings)](https://appshunter.io/ios/app/units-converter-for-engineers/id1018604081/reviews) | **[4.4 (7 ratings)](https://appshunter.io/ios/app/pdf-ocr-scanner-and-editor/id6738633268/reviews)** |
| Number of ratings | 2 | **7** |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 5 weeks | **Every 3 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 5 MB | 7 MB |
| Requires iOS | **16.6** | 17.0 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 17+ |
| Developer | [Lucy Enterprises](https://appshunter.io/developer/1656612108) | [Layerz Corp.](https://appshunter.io/developer/1617729865) |

## What reviewers say

### Units Converter for Engineers

[App page](https://appshunter.io/ios/app/units-converter-for-engineers/id1018604081)

This tool allows professionals and students to convert units and currencies using dimensional analysis. It supports a vast number of unit combinations and includes physical constants. Currency rates are updated monthly.

**Highlights:** Free-form unit conversion via dimensional analysis, Supports over 300 single units, Supports over 165 currencies with automatic updates, Includes dozens of physical constants, Identifies unit mismatches, Glossary of available units

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock all features | $0.99 | one-time |
| Remove ads | $1.99 | one-time |


### PDF OCR

[App page](https://appshunter.io/ios/app/pdf-ocr-scanner-and-editor/id6738633268)

This app offers a comprehensive suite of tools for managing PDF files. It allows you to extract text using OCR, convert PDFs to images, secure documents with passwords, and merge or split files. It also enables creating PDFs from images and converting webpages into PDF format, all while ensuring your data remains private through offline processing.

**Highlights:** Extract text with OCR, Convert PDF to images, Secure PDFs with passwords, Merge or split PDFs, Create PDFs from images, Convert webpages to PDF, Compress file size

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PDF OCR Pro Monthly | $3.99 | per month |
| PDF OCR Pro Yearly | $19.99 | per year |
| PDF OCR Pro Lifetime | $49.99 | one-time |


## Frequently asked questions

### Is Units Converter for Engineers free?

Units Converter for Engineers is free to download, with in-app purchases available.

### Is PDF OCR free?

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

### Which has better reviews, Units Converter for Engineers or PDF OCR?

PDF OCR is rated higher. Units Converter for Engineers averages 3.0 out of 5 from 2 ratings, while PDF OCR averages 4.4 from 7 ratings.

### Do Units Converter for Engineers or PDF OCR have ads?

Neither Units Converter for Engineers nor PDF OCR shows ads.

### Which is updated more often, Units Converter for Engineers or PDF OCR?

Units Converter for Engineers ships an update every 5 weeks, and PDF OCR every 3 weeks. Most recently, Units Converter for Engineers was updated on September 19, 2026 and PDF OCR 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.*