# ResToolbox3 vs PDF to ePUB

The clearest difference is in-app purchases: ResToolbox3 at none against PDF to ePUB's 3. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. PDF to ePUB sells 3 in-app purchases, starting at $2.99 per 7 days. ResToolbox3 asks for nothing beyond the download.

ResToolbox3 ships an update every 6 days, PDF to ePUB every 2 weeks. Both last shipped on October 31, 2026.

## The numbers

| Metric | ResToolbox3 | PDF to ePUB |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/restoolbox3/id6759464322/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 6 days** | Every 2 weeks |
| Monetization | **Free** | Free with in-app purchases |
| Size | 25 MB | 27 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [MobileReservoir](https://appshunter.io/developer/497057811) | [OMER FARUK KIZILTUG](https://appshunter.io/developer/1870337585) |

## What reviewers say

### ResToolbox3

[App page](https://appshunter.io/ios/app/restoolbox3/id6759464322)

This petroleum engineering calculator provides rapid answers for engineers in the field or office. It offers comprehensive tools for fluid properties, gas hydrate prediction, nodal analysis, production forecasting, volumetrics, and well testing, all accessible offline.

**Highlights:** Fluid properties (PVT) analysis, Gas hydrate prediction, Nodal analysis for wells, Production forecasting, Volumetric calculations, Well test analysis, Offline functionality

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

**In-app purchases:** none


### PDF to ePUB

[App page](https://appshunter.io/ios/app/pdf-to-epub-converter/id6760472933)

This tool converts PDF documents into reflowable ePUB ebooks directly on your device, ensuring complete privacy. It offers high-quality formatting, simple one-tap conversion, and cross-device compatibility within the Apple ecosystem.

**Highlights:** Local PDF to ePUB conversion, Preserves document formatting, One-tap conversion process, Cross-device Apple ecosystem support, Multiple subscription plans, Ad-free experience

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Premium | $2.99 | per 7 days |
| Annual Premium | $19.99 | per year |
| Lifetime Premium | $24.99 | one-time |


## Frequently asked questions

### Is ResToolbox3 free?

ResToolbox3 is free to download, with no in-app purchases.

### Is PDF to ePUB free?

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

### Do ResToolbox3 or PDF to ePUB have ads?

Neither ResToolbox3 nor PDF to ePUB shows ads.

### Which is updated more often, ResToolbox3 or PDF to ePUB?

ResToolbox3 ships an update every 6 days, and PDF to ePUB every 2 weeks. Most recently, ResToolbox3 was updated on October 31, 2026 and PDF to ePUB on October 31, 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.*