# Graycode vs 小灵龙App

The clearest difference is price: 小灵龙App at Free against Graycode's $2.99. 小灵龙App also leads on update cadence (monthly vs every 10 months) and ratings volume (12 vs 2). Graycode's advantage is rating (3.0 vs 1.0) and ads (none vs shown). On in-app purchases and device support there is nothing between them.

小灵龙App is free to download; Graycode costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Graycode holds the better App Store score, 3.0 against 1.0. That said, the two scores are not equally well evidenced: 小灵龙App has 12 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 67% of Graycode's written reviews are positive against 33% of 小灵龙App's.

Graycode ships an update every 10 months, 小灵龙App monthly. The most recent releases landed on August 26, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Graycode | 小灵龙App |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[3.0 (2 ratings)](https://appshunter.io/ios/app/graycode/id548428653/reviews)** | [1.0 (12 ratings)](https://appshunter.io/ios/app/app/id1221738240/reviews) |
| Number of ratings | 2 | **12** |
| Positive reviews | **66.7% of reviews** | 33.3% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 10 months | **Monthly** |
| Monetization | Paid | **Free** |
| Size | 2 MB | 157 MB |
| Requires iOS | 12.0 | **9.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Duo Pisceses, Inc.](https://appshunter.io/developer/850707063) | [北京新中新诚通信息技术股份有限公司](https://appshunter.io/developer/736575065) |

## What reviewers say

### Graycode

[App page](https://appshunter.io/ios/app/graycode/id548428653)

This utility converts numbers between decimal, hexadecimal, binary, and Gray code formats. Changes to one value automatically update the others, making it a convenient tool for engineers. It also features an animated demonstration of the Tower of Hanoi puzzle.

**Highlights:** Decimal, hex, binary, Gray code conversion, Real-time updates, Handy calculator for engineers, Animated Tower of Hanoi solution, Supports iPhone, iPad, iPod

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

**In-app purchases:** none


### 小灵龙App

[App page](https://appshunter.io/ios/app/app/id1221738240)

This app provides comprehensive mobile services for campus cards, including traditional card functions like consumption and authentication, enhanced with QR code capabilities. It offers features for managing your campus card, paying various campus fees, and booking campus facilities.

**Highlights:** Campus card management, QR code functionality, Campus fee payments, Facility booking, Card application and registration

**In-app purchases:** none


## Frequently asked questions

### Is Graycode free?

Graycode costs $2.99, with no in-app purchases.

### Is 小灵龙App free?

小灵龙App is free to download, with no in-app purchases.

### Which has better reviews, Graycode or 小灵龙App?

Graycode is rated higher. Graycode averages 3.0 out of 5 from 2 ratings, while 小灵龙App averages 1.0 from 12 ratings.

### Do Graycode or 小灵龙App have ads?

小灵龙App shows ads; Graycode does not.

### Which is updated more often, Graycode or 小灵龙App?

Graycode ships an update every 10 months, and 小灵龙App monthly. Most recently, Graycode was updated on August 26, 2026 and 小灵龙App on September 22, 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.*