# π ~PI~ vs Constant Challenge

The clearest difference is in-app purchases: π ~PI~ at none against Constant Challenge's 3. π ~PI~ also leads on iOS requirement (8.0 vs 26.0). Constant Challenge's advantage is update cadence (every 2 days vs every 6 months). On price, ads and device support there is nothing between them.

Both are free to download. Constant Challenge sells 3 one-off in-app purchases. π ~PI~ asks for nothing beyond the download.

π ~PI~ ships an update every 6 months, Constant Challenge every 2 days. The most recent releases landed on September 27, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | π ~PI~ | Constant Challenge |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 2 days** |
| Monetization | Free | — |
| Size | 23 MB | 16 MB |
| Requires iOS | **8.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Yuki Takeda](https://appshunter.io/developer/1021096508) | [Kaname Inoue](https://appshunter.io/developer/1888387338) |

## What reviewers say

### π ~PI~

[App page](https://appshunter.io/ios/app/pi/id1077740864)

Learn the digits of pi with engaging practice and challenge modes. Test your memory and see how many digits you can recall. Perfect for math enthusiasts and those looking to improve their memorization skills.

**Highlights:** Learn pi digits, Practice mode, Challenge mode, Memorize long sequences

**Features:** Vision Pro support

**In-app purchases:** none


### Constant Challenge

[App page](https://appshunter.io/ios/app/constant-challenge/id6761248442)

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock the Square Root of 2 (√2) | $0.99 | one-time |
| Unlock the Golden Ratio (φ) | $0.99 | one-time |
| Unlock the Euler–Mascheroni (γ) | $0.99 | one-time |


## Frequently asked questions

### Is π ~PI~ free?

π ~PI~ is free to download, with no in-app purchases.

### Is Constant Challenge free?

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

### Do π ~PI~ or Constant Challenge have ads?

Neither π ~PI~ nor Constant Challenge shows ads.

### Which is updated more often, π ~PI~ or Constant Challenge?

π ~PI~ ships an update every 6 months, and Constant Challenge every 2 days. Most recently, π ~PI~ was updated on September 27, 2026 and Constant Challenge on September 28, 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.*