# PDF Notes S vs Trench Calculator

The clearest difference is ads: Trench Calculator at none against PDF Notes S's shown. PDF Notes S's advantage is update cadence (every 6 weeks vs every 4 months) and iOS requirement (13.0 vs 15.1). On price, in-app purchases and device support there is nothing between them.

Both are free to download. PDF Notes S sells 2 in-app purchases, starting at $0.99 per month and Trench Calculator sells 1 in-app purchase, starting at $1.49 per month. Whichever you choose, the download price is not the number that matters.

PDF Notes S ships an update every 6 weeks, Trench Calculator every 4 months. The most recent releases landed on June 10, 2026 and September 5, 2026 respectively.

## The numbers

| Metric | PDF Notes S | Trench Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (5 ratings)](https://appshunter.io/ios/app/pdf-notes-s/id961336139/reviews)** | — |
| Number of ratings | **5** | — |
| Positive reviews | 52.9% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 6 weeks** | Every 4 months |
| Monetization | Free with in-app purchases | — |
| Size | 22 MB | 32 MB |
| Requires iOS | **13.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [AMuseTec Co., Ltd.](https://appshunter.io/developer/342152781) | [Linesite Tech](https://appshunter.io/developer/1879873664) |

## What reviewers say

### PDF Notes S

[App page](https://appshunter.io/ios/app/pdf-notes-s/id961336139)

This app offers a dual-page PDF viewer with smooth scrolling and fast page turns. It also provides document management, quick previews of various file types, and annotation tools. An upgrade removes ads and unlocks full functionality.

**Highlights:** Dual-page PDF viewer, Horizontal/vertical scroll and page turns, Document browser for file organization, Quick Look for various file types, ZIP file preview without unzipping, 8 handwriting tools, Cache manager for fast page turns

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Plan | $0.99 | per month |
| Yearly Plan | $9.99 | per year |


### Trench Calculator

[App page](https://appshunter.io/ios/app/trench-calculator/id6759792997)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Trench Calculator – Monthly Plan | $1.49 | per month |


## Frequently asked questions

### Is PDF Notes S free?

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

### Is Trench Calculator free?

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

### Do PDF Notes S or Trench Calculator have ads?

PDF Notes S shows ads; Trench Calculator does not.

### Which is updated more often, PDF Notes S or Trench Calculator?

PDF Notes S ships an update every 6 weeks, and Trench Calculator every 4 months. Most recently, PDF Notes S was updated on June 10, 2026 and Trench Calculator on September 5, 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.*