Multi-State Tax Calculator

A modern, professional web application for calculating state tax allocation when working across multiple states throughout the year. Perfect for remote workers, snowbirds, travelers, and anyone with multi-state tax obligations.

🌐 Live Application

🚀 Try it now at split.tax

The application is deployed and ready to use in production. No installation required - simply visit the link above to start calculating your multi-state tax allocation.

🎯 Who Needs This Tool?

Remote Workers: Digital nomads and remote employees working from different states
Snowbirds: Retirees and professionals who split time between seasonal residences
Business Travelers: Consultants and professionals with extended travel assignments
Temporary Residents: Contract workers, interns, or anyone with temporary state residency
Multi-State Employees: Workers whose job requires presence in multiple states

✨ Features

🗓️ Interactive Calendar-Based Pay Periods

Google Calendar-style Interface: Intuitive month navigation and visual period management
Weekday-Only View: Shows only Monday-Friday within visiting dates
Drag & Drop: Create pay periods by dragging across empty days
Click to Edit: Click colored days to edit gross taxable amounts
Color-Coded Periods: Each pay period has a unique visual identifier
Semi-Monthly Generation: Automatic 1st-15th and 16th-last day periods

🏛️ Advanced State Tax Management

Primary State Settings: Configure your main state of residence
Multi-State Support: Track days worked in different states
Tax Settings: Customizable tax rates and settings per state
Automatic Calculations: Proper tax allocation based on work days

📊 Professional Reporting

Detailed Results: Comprehensive breakdown of tax allocation
Pay Period Analysis: Individual period calculations and summaries
Export Ready: Professional reports for tax filing and record keeping

🔗 Google Calendar Integration

Automatic Import: Import work location events from Google Calendar
Multi-Calendar Support: Scan all your calendars for tax events
Smart Parsing: Recognizes [TAX] STATE format events
Seamless Sync: OAuth 2.0 integration for secure access

🎨 Modern User Experience

Responsive Design: Works perfectly on desktop, tablet, and mobile
Dark/Light Mode: System preference detection with manual toggle
Toast Notifications: Contextual feedback for user actions
Sticky Header: Always-accessible navigation and controls
Loading States: Professional loading indicators and error handling

🚀 Advanced Technical Features

State Management: Zustand-powered centralized state management
Local Storage: Automatic data persistence between sessions
Real-time Updates: Live calculation updates as you make changes
Type Safety: Full TypeScript implementation
Modern Architecture: React 18 with latest best practices

🛠️ Technology Stack

Frontend: React 18 + TypeScript
State Management: Zustand
Styling: Tailwind CSS
Build Tool: Vite
Icons: Lucide React
Integration: Google Calendar API
Storage: Browser LocalStorage

🚀 Quick Start

Prerequisites

Node.js 18+ and npm
Modern web browser
(Optional) Google account for calendar integration

Installation

Clone the repository

git clone https://github.com/yourusername/multi-state-tax-calculator.git
cd multi-state-tax-calculator

Install dependencies
```
npm install
```
Configure Google Calendar Integration (Optional)
- Create a Google Cloud Console project
- Enable the Google Calendar API
- Create OAuth 2.0 credentials
- Update src/config.ts with your client ID
Start development server
```
npm run dev
```
Open in browser
- Navigate to http://localhost:5173

Production Build

npm run build
npm run preview

📋 Usage Guide

1. Global Settings

Set your primary state of residence
Enter your visiting dates (work period)
Configure tax settings if needed

2. Other States

Add states where you worked temporarily
Use Google Calendar import to automatically populate work days
Or manually add dates for each state

3. Bonus Income

Add any bonus income received during the period
Specify the state where each bonus was earned

4. Pay Periods

Use the interactive calendar to create pay periods
Drag across days to create new periods
Click periods to edit gross taxable amounts
Use auto-generation for standard biweekly or semi-monthly periods

5. Calculate Results

Click "Calculate Allocation" to generate results
Review detailed breakdowns for each pay period
Export results for tax filing

🔧 Configuration

Google Calendar Setup

Google Cloud Console:
- Go to Google Cloud Console
- Create a new project or select existing one
- Enable the Google Calendar API
OAuth 2.0 Setup:
- Go to "Credentials" → "Create Credentials" → "OAuth 2.0 Client ID"
- Application type: "Web application"
- Authorized origins: http://localhost:5173 (for development)

Update Configuration:

// src/config.ts
export const CLIENT_ID = 'your-google-client-id.googleusercontent.com';

Tax Settings

Customize tax rates and settings in the application:

Access via the gear icon in Global Settings
Modify rates per state as needed
Settings are automatically saved locally

🎯 Calendar Event Format

For Google Calendar integration, use this format in your event titles:

[TAX] STATE_CODE - Description

Examples:

[TAX] CA - Working from San Francisco
[TAX] NY - Client meeting in New York
[TAX] FL - Remote work from Miami

🏗️ Project Structure

src/
├── components/           # React components
│   ├── Header.tsx       # Application header
│   ├── PayPeriodCalendar.tsx  # Interactive calendar
│   ├── ResultsPanel.tsx # Results display
│   └── ...
├── store.ts             # Zustand state management
├── types.ts             # TypeScript definitions
├── utils.ts             # Utility functions
├── config.ts            # Configuration settings
└── App.tsx              # Main application component

🤝 Contributing

We welcome contributions! Please follow these steps:

Fork the repository
Create a feature branch
```
git checkout -b feature/amazing-feature
```
Make your changes
Add tests if applicable
Commit your changes
```
git commit -m 'Add amazing feature'
```
Push to branch
```
git push origin feature/amazing-feature
```
Open a Pull Request

Development Guidelines

Follow TypeScript best practices
Use Prettier for code formatting
Write meaningful commit messages
Add JSDoc comments for complex functions
Ensure responsive design principles

📄 License

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

⚠️ Important Disclaimer

This tool is for informational purposes only and does not constitute tax advice. Always consult with a qualified tax professional for your specific situation. State tax laws vary and change frequently.

🆘 Support

Email: support@split.tax

🗺️ Roadmap

Additional state tax rule implementations
Export to popular tax software formats
Mobile app development
Advanced reporting features
Multi-year support
Integration with payroll systems

🎉 Acknowledgments

Built with modern React and TypeScript
Styled with Tailwind CSS
Icons by Lucide
State management by Zustand
Calendar integration with Google APIs

Made with ❤️ for remote workers, travelers, and multi-state professionals.

Name		Name	Last commit message	Last commit date
Latest commit History 15 Commits
.github/workflows		.github/workflows
public		public
src		src
.gitignore		.gitignore
README.md		README.md
eslint.config.js		eslint.config.js
index.html		index.html
package-lock.json		package-lock.json
package.json		package.json
styles.css		styles.css
tailwind.config.js		tailwind.config.js
tsconfig.app.json		tsconfig.app.json
tsconfig.json		tsconfig.json
tsconfig.node.json		tsconfig.node.json
vite.config.ts		vite.config.ts

evantobin/split.tax

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