2 guides
Mortgages
How mortgage debt behaves over 15 or 30 years, and where a dollar of extra principal is actually worth something. These guides run complete amortization schedules rather than quoting rules of thumb, including the fair comparison of a shorter term against investing the payment difference over the same horizon.
July 18, 2026 · 9 min read
The 15-Year Mortgage Wins Until You Can Earn 8%
A 15-year loan saves $322,507 in interest but costs $802.68 more every month. Invest that difference instead and the answer flips, but only above a return most people do not reliably get. Here is the exact crossover point.
July 2, 2026 · 8 min readAn Extra $300 a Month Saves $158,826 in Year One and $4,349 in Year 25
The same extra payment is worth thirty-six times more at the start of a mortgage than near the end. Amortization explains why, and it means the decision to prepay is really a decision about timing rather than amount.
Calculators for mortgages
Mortgage CalculatorEstimate your full monthly mortgage payment principal, interest, taxes, insurance, and HOA plus total interest over the life of the loan.Amortization CalculatorSee the full year-by-year amortization schedule for any loan: how each payment splits between principal and interest, and how the balance falls.Mortgage Payoff CalculatorFind out how much sooner your mortgage ends and how much interest you save when you add extra money to each monthly payment.