Overview
The Loan Payoff Calculator helps you optimize your debt elimination strategy by comparing multiple payoff scenarios. Save your loan portfolio, run different strategies, and see exactly how much you can save in interest and time.
Key Features
- Save unlimited loans with persistent storage (localStorage)
- Compare 4 payoff strategies: Baseline, Snowball, Avalanche, and Custom Order
- Configure extra payments with multiple frequency options
- Drag-and-drop custom loan payoff order
- Smart scenario expansion highlighting best strategies
- Calculate button highlights when changes need recalculation
- View detailed amortization schedules
- Export and import loan data for backup
- See interest saved and time saved comparisons
Getting Started
Step 1: Add Your Loans
Click the Add Loan button to enter loan details:
- Loan Name: A descriptive name (e.g., "Car Loan", "Visa Card")
- Balance: Current outstanding principal
- Interest Rate: Annual percentage rate (APR)
- Min Monthly Payment: Your current minimum payment
- Loan Type: Category for organization
Step 2: Configure Extra Payments
In the Scenario Builder, enter any extra monthly payment you can afford. This amount will be applied to the first loan in the payoff order, accelerating your debt freedom.
Step 3: Arrange Custom Order (Optional)
Drag and drop loans in the Custom Payoff Order section to create your own payoff sequence. This allows you to prioritize specific loans based on your personal preferences.
Step 4: Calculate Scenarios
Click Calculate All Scenarios to see four different payoff strategies compared side-by-side. The calculator automatically highlights the best strategies:
- Fastest Payoff: Strategy that gets you debt-free quickest
- Most Interest Saved: Strategy that minimizes total interest paid
Payoff Strategies Explained
Baseline (Minimum Payments)
Makes only the minimum required payments on all loans. This scenario shows what happens if you don't add any extra payments and serves as a reference point for comparing other strategies.
Best For: Understanding the cost of maintaining minimum payments
Snowball Method
Pays off the smallest balance first while making minimum payments on others. When a loan is paid off, that payment amount "snowballs" into the next smallest loan, creating momentum.
Best For: Quick psychological wins and motivation from eliminating debts fast
Strategy: Smallest balance [RIGHT ARROW] Largest balance
Avalanche Method
Pays off the highest interest rate first while making minimum payments on others. Mathematically optimal for minimizing total interest paid over the life of all loans.
Best For: Maximum interest savings and fastest debt elimination
Strategy: Highest interest rate to Lowest interest rate
Custom Order Method
Pays off loans in the order you specify by dragging and dropping in the Custom Payoff Order section. This lets you create a personalized strategy that balances your goals and priorities.
Best For: When you have specific reasons to target certain loans first
Strategy: Your custom sequence
Understanding Results
Comparison Table
The results table shows:
- Total Time: Months/years until all debts are paid
- Total Interest: Total interest you'll pay across all loans
- Interest Saved: How much less interest compared to baseline
- Time Saved: How much faster compared to baseline
- Payoff Date: Projected debt-free date
Recommendations
The calculator automatically identifies:
- Best for Interest Savings: Usually the Avalanche method
- Fastest Payoff: Depends on your extra payment and loan structure
Detailed View
After calculating, the best strategies are automatically expanded showing their details. Click any scenario's heading to expand or collapse its detailed view:
- Loan-by-loan breakdown
- Individual payoff dates
- Month-by-month amortization schedule
- Principal vs. interest for each payment
- Snowball and extra payment application (for strategy scenarios)
Managing Your Loans
Editing Loans
Click Edit next to any loan to update its information. This is useful when:
- Your balance changes
- Your interest rate is adjusted
- You refinance the loan
Deleting Loans
Click Delete to remove a paid-off or incorrect loan. You'll be asked to confirm.
Export/Import
- Export: Download your loan data as a JSON file for backup
- Import: Restore previously exported loan data
Tips for Success
- Start Small: Even $50-100 extra per month makes a significant difference
- Be Consistent: Regular extra payments compound over time
- Update Regularly: Recalculate after making extra payments or rate changes
- Choose Your Strategy: Snowball for motivation, Avalanche for savings
- Track Progress: Check your actual vs. projected payoff dates
Frequently Asked Questions
Q: Where is my data stored?
Your loan data is stored locally in your browser using localStorage. It never leaves your computer and is not sent to any server. This means your financial information stays completely private.
Q: What if I clear my browser data?
Clearing browser data will delete your saved loans. Use the Export feature to create a backup file that you can import later.
Q: Can I use this on different devices?
Currently, data is stored per-browser/device. To sync between devices, export from one and import to another.
Q: How accurate are the calculations?
The calculator uses standard amortization formulas with monthly compounding. Results are estimates based on the information you provide. Actual results may vary due to payment timing, rate changes, or fees.
Q: What if my payment doesn't cover the interest?
The calculator will show an error if your minimum payment is less than the monthly interest charge. This would cause negative amortization (growing balance). Increase your payment to exceed the monthly interest.
Technical Information
Calculation Method
The calculator uses the following formula for monthly interest calculation:
- Monthly Interest Rate = Annual Rate / 12
- Interest Charge = Current Balance × Monthly Rate
- Principal Payment = Total Payment - Interest Charge
- New Balance = Current Balance - Principal Payment
Browser Compatibility
Requires a modern browser with localStorage support:
- Chrome 4+
- Firefox 3.5+
- Safari 4+
- Edge (all versions)
Version History
Version 2.5.0 - November 13, 2025
- Removed automatic recalculation feature for better user control
- Added Calculate button highlighting (pulsing blue glow) when changes require recalculation
- Implemented smart scenario expansion: best strategies automatically expand while others collapse
- All four scenarios (Baseline, Snowball, Avalanche, Custom) remain fully accessible
- Improved user workflow: make changes, then manually trigger recalculation
- Enhanced visual feedback for data changes requiring attention
Version 2.4.0 - November 12, 2025
- Added Custom Order payoff strategy with drag-and-drop interface
- Implemented real-time auto-recalculation when custom order changes
- Added toggle for auto-recalculation preference
- Enhanced UI with draggable loan ordering
Version 2.3.0 - November 11, 2025
- Added simple username-based account system (no password required)
- Each user has their own separate loan portfolio
- Visual "Saved!" indicator appears when data is saved
- Welcome message with user's name
- Switch User button to manage multiple accounts
Version 2.2.0 - November 11, 2025 (Phase 1 MVP Complete)
- Complete UI redesign with modern interface
- LocalStorage persistence - loans automatically saved between sessions
- Dynamic loan management - add/edit/delete unlimited loans
- Three scenario comparison: Baseline, Snowball, and Avalanche
- Side-by-side comparison table showing best strategies
- Export/Import functionality for loan data backup (JSON format)
- Input validation and helpful error messages
- Statistics showing best options for interest savings and fastest payoff
- Detailed breakdown for each scenario with loan-by-loan results
Version 2.1.0 - November 10, 2025
- Separated extra payment from regular monthly payment
- Added extra payment frequency options (weekly, bi-weekly, monthly, quarterly, annually)
- Added detailed payment schedule with approximate dates (1st of each month)
- Payment schedule shows regular payment vs extra payment application
- Expandable details sections for each loan's amortization schedule
Version 2.0.1 - November 10, 2025
- Added WARP.md developer guidance file
Version 2.0.0 - November 10, 2025
- Complete redesign with modern UI
- Added localStorage for loan persistence
- Multiple scenario comparison (Baseline, Snowball, Avalanche)
- Detailed amortization schedules
- Export/Import functionality
- Improved calculation accuracy
- Mobile responsive design
Version 1.0.0 - Previous
- Basic loan payoff calculator
- Single snowball calculation
- Hardcoded extra payment
Support
For questions, feedback, or bug reports, contact:
Doug Hesseltine
Technologist.services
Version 2.5.0 | Last Modified: November 13, 2025
Author: Doug Hesseltine | Copyright Technologist.services 2025