# Learn Python in 21 Days vs PhD Challenge

The clearest difference is update cadence: PhD Challenge at every 3 weeks against Learn Python in 21 Days's every 2 months. Learn Python in 21 Days's advantage is iOS requirement (15 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Learn Python in 21 Days sells 2 in-app purchases, starting at $9.99 per month and PhD Challenge sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Learn Python in 21 Days ships an update every 2 months, PhD Challenge every 3 weeks. The most recent releases landed on October 24, 2026 and October 21, 2026 respectively.

## The numbers

| Metric | Learn Python in 21 Days | PhD Challenge |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (17 ratings)](https://appshunter.io/ios/app/learn-python-in-21-days/id6737173957/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 191 MB | 37 MB |
| Requires iOS | **15** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Adam Atamnia](https://appshunter.io/developer/1775084049) | [智慧 吴](https://appshunter.io/developer/1894708009) |

## What reviewers say

### Learn Python in 21 Days

[App page](https://appshunter.io/ios/app/learn-python-in-21-days/id6737173957)

Master Python programming with interactive lessons covering variables, data types, loops, functions, and more. Practice coding directly within the app and explore advanced topics like error handling and object-oriented programming.

**Highlights:** Variables, indentation, and comments, Data types: int, float, str, bool, list, tuple, set, dict, Control flow: conditions and loops, Functions and modules, Error handling and class basics, In-app coding practice

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Full Access | $9.99 | per month |
| Lifetime Full Access | $19.99 | one-time |


### PhD Challenge

[App page](https://appshunter.io/ios/app/phd-challenge/id6815483993)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Retake Ticket | $0.99 | one-time |
| 5 Retake Tickets | $2.99 | one-time |
| Unlimited Retakes | $9.99 | one-time |


## Frequently asked questions

### Is Learn Python in 21 Days free?

Learn Python in 21 Days is free to download, with in-app purchases available.

### Is PhD Challenge free?

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

### Do Learn Python in 21 Days or PhD Challenge have ads?

Neither Learn Python in 21 Days nor PhD Challenge shows ads.

### Which is updated more often, Learn Python in 21 Days or PhD Challenge?

Learn Python in 21 Days ships an update every 2 months, and PhD Challenge every 3 weeks. Most recently, Learn Python in 21 Days was updated on October 24, 2026 and PhD Challenge on October 21, 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.*