Mortgage Payoff Calculator - Amortization schedule with extra payments

I built this mortgage payoff calculator to deliver a truly comprehensive solution—one that goes beyond basic number-crunching. While most calculators only spit out simple monthly payment estimates, I noticed users often get stuck with real-world complexities: tracking existing balances, planning for a specific payoff date, or figuring out how irregular extra payments (like bonuses or tax refunds) impact their timeline. What makes this tool stand out? Three specialized calculation modes designed for every stage of your loan journey: - **Basic Calculation Mode**: Plan new loans with flexibility—supports monthly, annual, or one-time extra payments. - **Current Balance Mode**: For existing loans, instantly map out remaining payoff plans based on what you’ve already paid. - **Target Date Mode**: Reverse-engineer exactly what you need to pay to clear your mortgage by a specific date (e.g., before retirement). ### 🔹 **Flexible Extra Payment Tools** - Monthly extras (fixed amounts, added to your regular payment) - Annual lump sums (perfect for bonuses or windfalls) - One-time payments (custom amounts, scheduled for any month) ### 🔹 **Pro-Level Financial Insights** - Detailed amortization schedules: Break down every payment into principal, interest, and remaining balance. - Automatic savings tracking: See exactly how much you’ll save on interest (and time) with extra payments. - Excel-ready exports: Download CSVs to dive deeper into your numbers. - Shareable results: Generate links to collaborate with advisors or family. ### 🔹 **Built for Real Users** - No sign-ups required—jump in and calculate instantly. - Mobile-friendly design: Works smoothly on phones, tablets, or desktop. - Real-time results: Adjust numbers and see changes immediately. - Clear visuals: Charts and summaries that make complex data easy to grasp. ## 🎯 What’s Next? ### Coming Soon - **Equal Principal Support**: Add the "equal principal" repayment method alongside our existing equal-payment option. - **Bi-Weekly Payments**: Accelerate payoff with more frequent payment schedules. ### Short-Term Plans - **Prepayment vs. Investment Compare**: See whether paying down your mortgage or investing extra cash yields better returns (with NPV/IRR analysis). - **Penalty Optimization**: Smart tools to navigate prepayment penalties and minimize costs. - **Tax & Insurance Integration**: Fold in property taxes, insurance, and other variable costs for a full financial picture. ### Long-Term Vision - **Income-Based Affordability Checks**: Reverse-calculate how much home you can truly afford, based on your income. - **Professional Reports**: Export detailed analyses in PDF/Markdown (great for advisors or record-keeping). - **Multi-Scenario Comparisons**: Stack different repayment strategies side-by-side to pick the best one. - **Advanced Visuals**: Interactive charts to spot trends in interest, savings, and payoff timelines. ## 💡 Why This Matters This isn’t just another calculator—it’s a growing mortgage management system. We’ve built the tools you need today, with a roadmap to become your go-to for every decision (from taking out a loan to paying it off early). Whether you’re crunching numbers now or planning for the future, this tool evolves with you—turning complex mortgage math into clear, actionable steps toward financial freedom.