sl-nic-decoder

A smart Sri Lankan NIC decoding tool powered by Google Apps Script

🇱🇰 SL NIC Decoder (Sri Lanka)

A smart, lightweight web application to decode Sri Lankan National Identity Card (NIC) numbers. This tool supports both the Old (9-digit) and New (12-digit) formats, extracting vital information like Birthday, Gender, and Age instantly.

🔴 Click Here for Live Demo

(Click the link above to test the app)

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✨ Features

• 🔄 Auto Detection: Automatically identifies Old (19xxxxxxxV) vs New (200xxxxxxxxx) NIC formats.
• 📅 Birthday Calculation: Extracts the exact date of birth.
• 🚻 Gender Logic: Determines gender based on the day count value (Days > 500 = Female).
• ⏳ Age Calculator: Shows the current age accurately.
• 🎲 Lucky Number: A fun feature calculating a numerology number based on the birthday digits.
• 📱 Responsive UI: Built with Bootstrap 5 to look great on Mobile and PC.

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🧠 How It Works (The Logic)

This project uses a custom algorithm to reverse-engineer the NIC number logic used by the Department of Registration of Persons (Sri Lanka).

1. The 500 Rule (Gender)

In the SL NIC system, the day-of-year value represents the gender:

• Male: Days 1 - 366
• Female: Days 501 - 866

The code checks if (days > 500) { Gender = Female; Days = Days - 500; }

2. The Leap Year Standard

Since the NIC department utilizes a static calendar assumption (assuming February always has 29 days for indexing), the algorithm uses a Leap Year Reference (2024) to map the day count back to the exact Month and Date. This ensures accuracy for all birth years.

3. Old vs New Format

• Old Format: The first two digits represent the year (19xx).
• New Format: The first four digits represent the full year.

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🛠️ Tech Stack

• Frontend: HTML5, CSS3, Bootstrap 5 (for Glassmorphism UI)
• Backend: Google Apps Script (.gs)
• Deployment: Google Web App Service

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🚀 How to Run Your Own Copy

1. Go to script.google.com.
2. Create a new project.
3. Copy the contents of Code.js into Code.gs.
4. Create an index.html file and copy the HTML code.
5. Click Deploy > New Deployment > Web App.
6. Set "Who has access" to "Anyone".

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👨‍💻 Author

Developed by Kasun Charitha. Building smart solutions for everyday problems.

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Disclaimer: This tool is for educational and utility purposes only. It decodes data embedded in the public NIC number format and does not access any government database.