# HydroCalc Plus vs PDFSignerScanner

The clearest difference is price: PDFSignerScanner at Free against HydroCalc Plus's $6.99. On review sentiment, update cadence, ads and in-app purchases there is nothing between them.

PDFSignerScanner is free to download; HydroCalc Plus costs $6.99 up front. HydroCalc Plus sells 4 one-off in-app purchases and PDFSignerScanner sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

HydroCalc Plus ships an update every 3 weeks, PDFSignerScanner every 11 days. The most recent releases landed on October 23, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | HydroCalc Plus | PDFSignerScanner |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/hydrocalc-plus/id578807688/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 11 days** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 34 MB | 13 MB |
| Requires iOS | **15.1** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Transparent Blue Water LLC](https://appshunter.io/developer/1847968351) | [MANJUR KOLHAR](https://appshunter.io/developer/1845533906) |

## What reviewers say

### HydroCalc Plus

[App page](https://appshunter.io/ios/app/hydrocalc-plus/id578807688)

A professional tool for hydraulic engineers to calculate pressure losses in piping systems. It supports US and SI units, offers an extensive pipe material and fittings database, and includes inverse calculations for design optimization.

**Highlights:** Friction head loss calculation (Hazen-Williams), US and SI unit support, Extensive pipe material library, Fittings and valves database, Inverse calculation mode, Real-time results (velocity, losses)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pump Power Calculator | $1.99 | one-time |
| System Curve Generator | $1.99 | one-time |
| Pipe Database | $1.99 | one-time |
| Industrial Fluids Pack | $2.99 | one-time |


### PDFSignerScanner

[App page](https://appshunter.io/ios/app/pdfsignerscanner/id6754396681)

Easily add your signature to PDF documents. Create a signature by drawing, taking a photo, or importing an image. The app allows you to customize placement, size, and ink color before exporting a final, shareable PDF.

**Highlights:** Signature creation (draw, photo, import), Signature background cleaning, Signature cropping, Customizable signature placement, Multiple ink colors, Export signed PDFs

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Unlock | $4.99 | one-time |


## Frequently asked questions

### Is HydroCalc Plus free?

HydroCalc Plus costs $6.99, and also offers in-app purchases.

### Is PDFSignerScanner free?

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

### Do HydroCalc Plus or PDFSignerScanner have ads?

Neither HydroCalc Plus nor PDFSignerScanner shows ads.

### Which is updated more often, HydroCalc Plus or PDFSignerScanner?

HydroCalc Plus ships an update every 3 weeks, and PDFSignerScanner every 11 days. Most recently, HydroCalc Plus was updated on October 23, 2026 and PDFSignerScanner on October 6, 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.*