# PK vs Sigma

The clearest difference is price: Sigma at Free against PK's $99.99. Sigma also leads on update cadence (every 4 days vs every 2 months). PK's advantage is iOS requirement (16.0 vs 18.0). On ads, in-app purchases and device support there is nothing between them.

Sigma is free to download; PK costs $99.99 up front. Neither carries in-app purchases, so what you see is what you pay.

PK ships an update every 2 months, Sigma every 4 days. The most recent releases landed on October 20, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | PK | Sigma |
| --- | --- | --- |
| Price | $99.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/pk-ink-pro/id6717616357/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 4 days** |
| Monetization | Paid | — |
| Size | 16 MB | 7 MB |
| Requires iOS | **16.0** | 18.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Nelson Suarez Arteaga](https://appshunter.io/developer/1692733605) | [MAJOR Productions LLC](https://appshunter.io/developer/1885618341) |

## What reviewers say

### PK

[App page](https://appshunter.io/ios/app/pk-ink-pro/id6717616357)

Create a paranormal illusion by magically moving permanent ink on your mobile screen. Spectators choose ink placement and color, and you control the movement remotely or with hand gestures. Offers multiple finales and can integrate with other magic apps for advanced effects.

**Highlights:** Spectator-chosen ink placement, Customizable marker colors and designs, Remote control and hand-gesture recognition, Multiple powerful finales, Offline functionality, Integration with other magic apps

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

**In-app purchases:** none


### Sigma

[App page](https://appshunter.io/ios/app/sigma-calculator/id6760669373)

**In-app purchases:** none


## Frequently asked questions

### Is PK free?

PK costs $99.99, with no in-app purchases.

### Is Sigma free?

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

### Do PK or Sigma have ads?

Neither PK nor Sigma shows ads.

### Which is updated more often, PK or Sigma?

PK ships an update every 2 months, and Sigma every 4 days. Most recently, PK was updated on October 20, 2026 and Sigma on October 23, 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.*