How Mortgage Amortization & Bi-Weekly Payments Save Thousands
How Early Principal Reduction Works
Fixed-rate mortgages calculate interest monthly based on your remaining loan balance. During the first decade, a large portion of your payment goes toward interest. Adding extra principal directly reduces the base on which future interest compounds.
Mathematical Formula & Bi-Weekly Effect
Monthly payment follows M = P [ r(1 + r)^n ] / [ (1 + r)^n – 1 ]. Switching to bi-weekly payments splits your monthly payment in half every two weeks, resulting in 26 half-payments (13 full payments) per year—effortlessly adding one full extra payment annually.
Frequently Asked Questions
Is bi-weekly payment better than adding extra monthly principal? +
Bi-weekly payments automatically create 13 monthly payments per year instead of 12. However, adding a fixed extra monthly amount gives you full flexibility and can save even more if you contribute higher amounts.
Should I pay off my mortgage early or invest in index funds? +
Compare your mortgage interest rate against expected after-tax investment returns. If your mortgage rate exceeds 6%, paying down debt offers a guaranteed risk-free return equal to that interest rate.
Are there prepayment penalties on mortgages? +
Most modern residential mortgages allow extra principal payments without penalty, though some fixed-period loans in Europe or Asia cap annual overpayments at 5%–10%. Always verify with your lender.