# Kỳ Phổ Số vs Chess Clock

The clearest difference is update cadence: Kỳ Phổ Số at every 4 days against Chess Clock's fortnightly. Kỳ Phổ Số also leads on iOS requirement (15.0 vs 26.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Kỳ Phổ Số sells 15 one-off in-app purchases and Chess Clock sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

Kỳ Phổ Số ships an update every 4 days, Chess Clock fortnightly. The most recent releases landed on October 8, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Kỳ Phổ Số | Chess Clock |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 4 days** | Fortnightly |
| Size | 207 MB | 18 MB |
| Requires iOS | **15.0** | 26.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nguyen Thanh Trung](https://appshunter.io/developer/1896476071) | [Naveen Mathivanan](https://appshunter.io/developer/1870850926) |

## What reviewers say

### Kỳ Phổ Số

[App page](https://appshunter.io/ios/app/ky-pho-so/id6767448760)

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

**In-app purchases (15)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Sát pháp-N-Khó | $1.99 | one-time |
| Sát pháp-O-Khó | $1.99 | one-time |
| Sát pháp-P-Khó | $1.99 | one-time |
| Sát pháp-Q-Khó | $1.99 | one-time |
| Sát pháp-R-Khó | $1.99 | one-time |
| Sát pháp Luyện tập - D - Mức độ dễ | $1.99 | one-time |
| Sát pháp Luyện tập - E - Mức độ dễ | $1.99 | one-time |
| Sát pháp Luyện tập - F - Mức độ dễ | $1.99 | one-time |
| Sát pháp-G-Trung bình | $1.99 | one-time |
| Sát pháp-H-Trung bình | $1.99 | one-time |
| Sát pháp-I-Trung bình | $1.99 | one-time |
| Sát pháp-J-Trung bình | $1.99 | one-time |
| Sát pháp-K-Trung bình | $1.99 | one-time |
| Sát pháp-L-Khó | $1.99 | one-time |
| Sát pháp-M-Khó | $1.99 | one-time |


### Chess Clock

[App page](https://appshunter.io/ios/app/chess-clock-dual-timer/id6797176383)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Chess Clock Pro Monthly | $1.99 | per month |
| Chess Clock Pro Annual | $9.99 | per year |
| Chess Clock Pro Lifetime | $14.99 | one-time |


## Frequently asked questions

### Is Kỳ Phổ Số free?

Kỳ Phổ Số is free to download, with in-app purchases available.

### Is Chess Clock free?

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

### Do Kỳ Phổ Số or Chess Clock have ads?

Neither Kỳ Phổ Số nor Chess Clock shows ads.

### Which is updated more often, Kỳ Phổ Số or Chess Clock?

Kỳ Phổ Số ships an update every 4 days, and Chess Clock fortnightly. Most recently, Kỳ Phổ Số was updated on October 8, 2026 and Chess Clock on October 5, 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.*