# QiMenChart vs Polygon

The clearest difference is price: Polygon at Free against QiMenChart's $6.99. Polygon also leads on update cadence (weekly vs every 6 months). QiMenChart's advantage is in-app purchases (none vs 4) and iOS requirement (15.6 vs 17.0). On ads and device support there is nothing between them.

Polygon is free to download; QiMenChart costs $6.99 up front. Polygon sells 4 in-app purchases, starting at $2.99 per month. QiMenChart asks for nothing beyond the download.

QiMenChart ships an update every 6 months, Polygon weekly. The most recent releases landed on October 8, 2026 and September 20, 2026 respectively.

## The numbers

| Metric | QiMenChart | Polygon |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Rating | — | **[3.0 (1 ratings)](https://appshunter.io/ios/app/polygon-inertia-centroid/id6469235285/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 months | **Weekly** |
| Monetization | Paid | **Freemium** |
| Size | 6 MB | 29 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [LAY KHIM TAN](https://appshunter.io/developer/738497892) | [Adrian Caballero](https://appshunter.io/developer/1635287590) |

## What reviewers say

### QiMenChart

[App page](https://appshunter.io/ios/app/qimenchart/id1028901400)

This app generates historical charts for years, months, days, and hours using traditional Chinese calendrical methods. It allows users to orient the chart with a compass based on their position. The application focuses solely on chart plotting without providing any analysis or user settings.

**Highlights:** Plot Year, Month, Day, Hour Charts, Chai Bu and Zhi Run Methods, Year Range 1800-9999, Compass Orientation, Chart Plotting Only

**In-app purchases:** none


### Polygon

[App page](https://appshunter.io/ios/app/polygon-inertia-centroid/id6469235285)

Calculate complex properties of any polygonal figure, including centroids, moments of inertia, and perimeter. Simply input vertex coordinates for instant results, saving significant time on tedious calculations.

**Highlights:** Polygon Centroids, Moments of Inertia (Ix, Iy, Ixy), Polar Moment of Inertia, Radius of Gyration, Principal Moments of Inertia, Area and Perimeter, Side Lengths, Hollow Sections

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Access | $2.99 | per month |
| Pro Access | $4.99 | per 6 months |
| Pro Access | $6.99 | per year |
| Pro Access | $9.99 | one-time |


## Frequently asked questions

### Is QiMenChart free?

QiMenChart costs $6.99, with no in-app purchases.

### Is Polygon free?

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

### Do QiMenChart or Polygon have ads?

Neither QiMenChart nor Polygon shows ads.

### Which is updated more often, QiMenChart or Polygon?

QiMenChart ships an update every 6 months, and Polygon weekly. Most recently, QiMenChart was updated on October 8, 2026 and Polygon on September 20, 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.*