# Physical Constants vs PFD Calc

The clearest difference is update cadence: PFD Calc at every 5 weeks against Physical Constants's every 9 months. Physical Constants's advantage is iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Physical Constants ships an update every 9 months, PFD Calc every 5 weeks. The most recent releases landed on August 24, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | Physical Constants | PFD Calc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.3 (3 ratings)](https://appshunter.io/ios/app/physical-constants-ml/id837679891/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 33.3% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | Every 9 months | **Every 5 weeks** |
| Monetization | Ad-supported | — |
| Size | 25 MB | 14 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Takuya Ishikawa](https://appshunter.io/developer/468311118) | [Kazuhisa Kobayashi](https://appshunter.io/developer/1580882000) |

## What reviewers say

### Physical Constants

[App page](https://appshunter.io/ios/app/physical-constants-ml/id837679891)

Access a comprehensive list of physical constants, organized by category for easy searching. This app supports all AppStore languages and allows users to report corrections via email.

**Highlights:** Physical constants database, Categorized by topic, Search functionality, Multi-language support, User feedback for corrections

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

**In-app purchases:** none


### PFD Calc

[App page](https://appshunter.io/ios/app/pfd-calc-prime-factorization/id6737405828)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Physical Constants free?

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

### Is PFD Calc free?

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

### Do Physical Constants or PFD Calc have ads?

Both Physical Constants and PFD Calc show ads.

### Which is updated more often, Physical Constants or PFD Calc?

Physical Constants ships an update every 9 months, and PFD Calc every 5 weeks. Most recently, Physical Constants was updated on August 24, 2026 and PFD Calc on September 17, 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.*