# 天球模擬器 vs 單字雪球

The clearest difference is in-app purchases: 天球模擬器 at none against 單字雪球's 1. 天球模擬器 also leads on iOS requirement (13.0 vs 17.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. 單字雪球 sells 1 one-off in-app purchase. 天球模擬器 asks for nothing beyond the download.

天球模擬器 ships an update every 3 days, 單字雪球 every 4 days. The most recent releases landed on October 25, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | 天球模擬器 | 單字雪球 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/7000/id6799845340/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 days** | Every 4 days |
| Monetization | — | Free |
| Size | 19 MB | 34 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Han-Chiang Chou](https://appshunter.io/developer/1883578938) | [CHENG-LI CHANG](https://appshunter.io/developer/6799845342) |

## What reviewers say

### 天球模擬器

[App page](https://appshunter.io/ios/app/id6760458030)

**Features:** macOS Compatibility

**In-app purchases:** none


### 單字雪球

[App page](https://appshunter.io/ios/app/7000/id6799845340)

This app uses spaced repetition to help you master difficult vocabulary. It features a built-in dictionary, multiple learning modes, and progress tracking. Designed for those who already know many words, it focuses on reinforcing what you struggle to remember.

**Highlights:** Spaced Repetition System (SRS), 18,000+ built-in word bank, Four learning modes (read, quiz, spell, sprint), Built-in Cambridge Dictionary, Progress sync via iCloud, No account, ads, or subscriptions

**Features:** Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 記憶線索 | $2.99 | one-time |


## Frequently asked questions

### Is 天球模擬器 free?

天球模擬器 is free to download, with no in-app purchases.

### Is 單字雪球 free?

單字雪球 is free to download, with in-app purchases available.

### Do 天球模擬器 or 單字雪球 have ads?

Neither 天球模擬器 nor 單字雪球 shows ads.

### Which is updated more often, 天球模擬器 or 單字雪球?

天球模擬器 ships an update every 3 days, and 單字雪球 every 4 days. Most recently, 天球模擬器 was updated on October 25, 2026 and 單字雪球 on October 29, 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.*