About This Calculator
What We Built
This is a fast, privacy-first mortgage amortization calculator. It's designed to be:
- Instant: Calculations happen in your browser with no delays or API calls.
- Private: Your loan data never leaves your device. We don't store or track it.
- Accurate: Uses the standard amortization formula with full precision.
- Simple: Clean interface, no fluff, just the tools you need.
How It Works
Enter your loan amount, annual interest rate, term length, and (optionally) extra monthly payments. The calculator uses the standard amortization formula to compute:
- Your monthly principal & interest (P&I) payment
- Total interest you'll pay over the life of the loan
- Your exact payoff date
- A complete month-by-month amortization schedule
All calculations are done in JavaScript in your browser using double-precision floating-point arithmetic. Results are rounded to the nearest cent, just like your bank would.
Technology
This site is built with Astro and deploys as a static HTML site. It uses zero JavaScript frameworks—just vanilla TypeScript for the calculator logic. The entire site is optimized for speed and minimal bandwidth.
Disclaimer
This calculator is provided for educational and informational purposes only. Actual mortgage payments may differ based on loan fees, property taxes, homeowners insurance, PMI, HOA fees, and other factors. Always consult your lender for accurate quotes and loan terms.