💰 Post-Judgment Interest Calculator

A Professional Desktop Application for Legal Interest Calculations

Calculate post-judgment interest rates for federal and state jurisdictions across the United States

Download Latest Release • Report Bug • Request Feature

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📋 Table of Contents

• ✨ Features
• 🖼️ Screenshots
• 🚀 Quick Start
• 💻 Installation
  • Windows MSI Installer (Recommended)
  • Build from Source
• 📖 User Guide
  • Calculator Tab
  • Database Manager Tab
  • Settings Tab
• 🛠️ Tech Stack
• 🏗️ Architecture
• 📊 How It Works
• 🧩 Project Structure
• 🔧 Development
• 🤝 Contributing
• 📄 License
• 🙏 Acknowledgments

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✨ Features

🏛️ Federal Rate Calculations Automatically fetches real-time federal interest rates from the FRED API (1-Year Treasury Constant Maturity Rate) 🗺️ All 50 States + DC Pre-populated database with interest rates for all U.S. jurisdictions ✏️ Database Management Built-in UI for viewing, editing, adding, and deleting state interest rates

📊 Simple Interest Formula Uses the standard formula: Principal × Rate × (Days / 365) 📅 Flexible Date Ranges Calculate interest for any date range with intuitive date pickers 🔐 Secure API Storage Local storage of FRED API key with easy configuration

🌐 Cross-Platform Support

• ✅ Windows (MSI installer available for x64 and ARM64)
• ✅ macOS (Build from source)
• ✅ Linux (Build from source)

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🖼️ Screenshots

📊 Calculator Tab Calculate interest with ease	🗃️ Database Manager Manage state rates efficiently	⚙️ Settings Configure your API key

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🚀 Quick Start

1. Download the installer from the Releases page
2. Install the application
3. Get your FREE API key from FRED
4. Configure your API key in the Settings tab
5. Start calculating post-judgment interest!

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💻 Installation

Option 1: Windows MSI Installer (Recommended)

💿 x64 Version For most Windows PCs (Intel/AMD processors)

💿 ARM64 Version For ARM-based devices (Surface Pro X, etc.)

Installation Steps:

1. Download the appropriate MSI for your system architecture
2. Double-click the downloaded file to run the installer
3. Follow the installation wizard
4. Launch the app from your Start Menu

Option 2: Build from Source

📦 Prerequisites

• Rust (latest stable)
• Node.js (v18 or higher)
• Tauri CLI

🔨 Build Steps

# Clone the repository
git clone https://github.com/matt793/JudgmentRateDesktop.git
cd JudgmentRateDesktop

# Install dependencies
npm install

# Run development server
npm run tauri dev

# Build for production
npm run tauri build

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📖 User Guide

Calculator Tab

The main interface for calculating post-judgment interest:

1. Select Jurisdiction: Choose between Federal or any U.S. state
2. Enter Judgment Date: The date the judgment was entered
3. Enter Amount: The principal judgment amount
4. Select Date Range: Choose start and end dates for interest calculation
5. Calculate: Click to see results including:
   • Applied interest rate
   • Number of days
   • Total interest amount
   • Legal disclaimer

💡 Tip: Federal rates are fetched automatically based on the judgment date!

Database Manager Tab

Manage state interest rates with an intuitive interface:

• View all state rates in a sortable grid
• Edit rates by double-clicking cells
• Search for specific states
• Filter by rate type (fixed/variable)
• Add new jurisdictions
• Delete outdated entries

Rate Types:

• Fixed Rate: A specific percentage (e.g., 8%)
• Variable Rate: Federal rate + additional percentage

Settings Tab

Configure your FRED API key:

1. Get your API key:

   • Visit FRED API Registration
   • Create a free account
   • Request an API key (instant approval)

2. Enter the key in the settings

3. Save to enable federal rate calculations

🔒 Security: Your API key is stored locally and never transmitted except to FRED's servers.

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🛠️ Tech Stack

Backend (Rust) 🦀

Technology	Purpose
Tauri	Desktop application framework
SQLite	Local database via rusqlite
reqwest	HTTP client for FRED API
chrono	Date handling and calculations
serde	JSON serialization
thiserror	Error handling
dotenvy	Environment management

Frontend (TypeScript/React) ⚛️

Technology	Purpose
React	UI framework
TypeScript	Type-safe JavaScript
Vite	Build tool and dev server
Tailwind CSS	Utility-first styling
React DatePicker	Date selection
Tauri API	Backend communication

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🏗️ Architecture

graph TB
    A[React Frontend] -->|Tauri IPC| B[Rust Backend]
    B --> C[SQLite Database]
    B --> D[FRED API]
    B --> E[Interest Calculator]
    
    C --> F[State Rates]
    D --> G[Federal Rates]
    
    E --> H[Results]
    H --> A

Loading

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📊 How It Works

Federal Rate Calculation

1. Week Determination: Identifies the week preceding the judgment date (Monday-Sunday)
2. API Call: Fetches daily 1-Year Treasury yields from FRED
3. Average Calculation: Computes average of valid yields (skips missing data)
4. Rate Conversion: Converts percentage to decimal

State Rate Handling

• Storage: Local SQLite database
• Types:
  • Fixed: Specific percentage rate
  • Variable: Federal rate + additional percentage
• Management: Full CRUD operations via Database Manager

⚠️ Important Note: State interest rates are subject to change and may be updated by state legislatures. While this application comes pre-populated with current rates, you should verify and manually update state rates periodically through the Database Manager tab to ensure accuracy. Always consult official state sources or legal counsel for the most current rates.

Interest Calculation

Interest = Principal × Rate × (Days / 365)

• Days calculated inclusively
• Results rounded to 2 decimal places
• Includes legal disclaimer

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🧩 Project Structure

JudgmentRateDesktop/
├── 📁 src/                      # React frontend
│   ├── 📁 components/           # UI components
│   │   ├── 📄 CalculatorTab.tsx
│   │   ├── 📄 DbManagerTab.tsx
│   │   └── 📄 SettingsTab.tsx
│   ├── 📄 App.tsx               # Main app
│   ├── 📄 types.ts              # TypeScript types
│   └── 📄 main.tsx              # Entry point
│
├── 📁 src-tauri/                # Rust backend
│   ├── 📁 src/
│   │   ├── 📄 main.rs           # App entry
│   │   ├── 📄 commands.rs       # Tauri commands
│   │   ├── 📄 db.rs             # Database ops
│   │   ├── 📄 rate_fetcher.rs   # FRED API
│   │   └── 📄 calculator.rs     # Interest calc
│   └── 📄 Cargo.toml            # Rust deps
│
├── 📁 RMImages/                 # Screenshots
└── 📄 package.json              # Node deps

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🔧 Development

Database Schema

CREATE TABLE state_rates (
    id INTEGER PRIMARY KEY,
    state TEXT NOT NULL UNIQUE,
    rate REAL NOT NULL,
    is_variable INTEGER NOT NULL DEFAULT 0,
    plus_percentage REAL DEFAULT 0,
    update_frequency TEXT,
    last_update TEXT,
    notes TEXT
);

Running Tests

# Rust tests
cd src-tauri
cargo test

# Frontend tests
npm test

Updating Dependencies

# Rust dependencies
cd src-tauri
cargo update

# Node dependencies
npm update

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🤝 Contributing

We welcome contributions! Here's how you can help:

1. 🍴 Fork the repository
2. 🌿 Create a feature branch (git checkout -b feature/AmazingFeature)
3. 💾 Commit your changes (git commit -m 'Add AmazingFeature')
4. 📤 Push to the branch (git push origin feature/AmazingFeature)
5. 🔄 Open a Pull Request

Code Style

• Rust: Follow standard Rust formatting (cargo fmt)
• TypeScript: Use Prettier and ESLint configurations
• Commits: Use conventional commit messages

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📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

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🙏 Acknowledgments

Special thanks to:

🏦 Federal Reserve Economic Data (FRED) for providing reliable interest rate data

🚀 Tauri for the amazing desktop framework

⚛️ React and 🦀 Rust communities

📚 All contributors and users of this application

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🎵 Built with Vibes

This entire application was "Vibe Coded" - built through an interactive, conversational coding session where we explored ideas, iterated on solutions, and created something awesome together. Sometimes the best code comes from good vibes and collaborative energy! ✨

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📧 Support

For issues, questions, or suggestions, please open an issue on GitHub.

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Made with ❤️ by matt793