# PDF Notes S vs Quadrant Magnetics Calculator

The clearest difference is rating: Quadrant Magnetics Calculator at 5.0 against PDF Notes S's 4.2. Quadrant Magnetics Calculator also leads on in-app purchases (none vs 2) and ads (none vs shown). PDF Notes S's advantage is iOS requirement (13.0 vs 15.1). On price, ratings volume, update cadence 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. Quadrant Magnetics Calculator asks for nothing beyond the download.

Quadrant Magnetics Calculator holds the better App Store score, 5.0 against 4.2. Both are backed by a comparable volume of ratings — 5 and 2 respectively.

PDF Notes S ships an update every 6 weeks, Quadrant Magnetics Calculator every 2 months. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | PDF Notes S | Quadrant Magnetics Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.2 (5 ratings)](https://appshunter.io/ios/app/pdf-notes-s/id961336139/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/quadrant-magnetics-calculator/id1326461266/reviews)** |
| Number of ratings | **5** | 2 |
| Positive reviews | 52.9% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 6 weeks** | Every 2 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 22 MB | 26 MB |
| Requires iOS | **13.0** | 15.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [AMuseTec Co., Ltd.](https://appshunter.io/developer/342152781) | [Quadrant International](https://appshunter.io/developer/1887506007) |

## 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 |


### Quadrant Magnetics Calculator

[App page](https://appshunter.io/ios/app/quadrant-magnetics-calculator/id1326461266)

Calculate magnetic force, permeance coefficient, and demagnetizing factor for various magnet shapes. Input magnet dimensions and grade or Br value to get results based on computer simulation data.

**Highlights:** Calculate magnetic force, Calculate permeance coefficient, Calculate demagnetizing factor, Supports rectangular blocks, Supports axially magnetized rings, Supports axially magnetized cylinders

**In-app purchases:** none


## Frequently asked questions

### Is PDF Notes S free?

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

### Is Quadrant Magnetics Calculator free?

Quadrant Magnetics Calculator is free to download, with no in-app purchases.

### Which has better reviews, PDF Notes S or Quadrant Magnetics Calculator?

Quadrant Magnetics Calculator is rated higher. PDF Notes S averages 4.2 out of 5 from 5 ratings, while Quadrant Magnetics Calculator averages 5.0 from 2 ratings.

### Do PDF Notes S or Quadrant Magnetics Calculator have ads?

PDF Notes S shows ads; Quadrant Magnetics Calculator does not.

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

PDF Notes S ships an update every 6 weeks, and Quadrant Magnetics Calculator every 2 months. Most recently, PDF Notes S was updated on November 1, 2026 and Quadrant Magnetics Calculator on November 2, 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.*