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.

🚀 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.

Multi-State Tax Calculator Version License Live Site

• 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

• 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

• 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

• 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

• 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

• 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

• 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

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

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

1. Clone the repository

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

2. Install dependencies

   npm install

3. 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

4. Start development server

   npm run dev

5. Open in browser

   • Navigate to http://localhost:5173

npm run build
npm run preview

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

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

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

• 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

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

1. Google Cloud Console:

   • Go to Google Cloud Console
   • Create a new project or select existing one
   • Enable the Google Calendar API

2. 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)

3. Update Configuration:

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

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

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

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

We welcome contributions! Please follow these steps:

1. Fork the repository
2. Create a feature branch

   git checkout -b feature/amazing-feature

3. Make your changes
4. Add tests if applicable
5. Commit your changes

   git commit -m 'Add amazing feature'

6. Push to branch

   git push origin feature/amazing-feature

7. Open a Pull Request

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

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

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.

• Email: support@split.tax

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

• 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.