# PDFly vs Calculation Transformers

The clearest difference is update cadence: PDFly at every 2 months against Calculation Transformers's every 5 months. Calculation Transformers's advantage is iOS requirement (13.0 vs 15.5). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. PDFly sells 2 in-app purchases, starting at $2.99 per month and Calculation Transformers sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

PDFly ships an update every 2 months, Calculation Transformers every 5 months. Both last shipped on October 31, 2026.

## The numbers

| Metric | PDFly | Calculation Transformers |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/calculation-transformers/id6759037556/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 5 months |
| Monetization | — | Free with in-app purchases |
| Size | 85 MB | 56 MB |
| Requires iOS | 15.5 | **13.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Senkronix Kurumsal](https://appshunter.io/developer/1068453339) | [Nanjibhai Gorasiya](https://appshunter.io/developer/1834066312) |

## What reviewers say

### PDFly

[App page](https://appshunter.io/ios/app/pdfly-pdf-scanner-and-editor/id6758089329)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PDFly Premium Monthly | $2.99 | per month |
| PDFly Premium Yearly | $14.99 | per year |


### Calculation Transformers

[App page](https://appshunter.io/ios/app/calculation-transformers/id6759037556)

This electrical engineering tool simplifies complex transformer calculations for students and professionals. It offers fast, accurate results in an easy-to-understand format, aiding in design, maintenance, and analysis.

**Highlights:** Fast transformer calculations, Clear input structure, Accurate results, Design and troubleshooting aid, User-friendly interface

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime premium | $9.99 | one-time |


## Frequently asked questions

### Is PDFly free?

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

### Is Calculation Transformers free?

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

### Do PDFly or Calculation Transformers have ads?

Neither PDFly nor Calculation Transformers shows ads.

### Which is updated more often, PDFly or Calculation Transformers?

PDFly ships an update every 2 months, and Calculation Transformers every 5 months. Most recently, PDFly was updated on October 31, 2026 and Calculation Transformers 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.*