CalculynQuick answer
A $300,000 balance at 6.5% with 25 years left costs about $2,026/month. Adding $200/month pays it off ~3.5 years early and saves roughly $48,000 in interest.
How it works
Extra payments go straight to principal, so less interest accrues every following month. Even a small extra amount can cut years off a long loan.
Formula
Payoff months = −ln(1 − P·r÷pay) ÷ ln(1 + r), where r = annual rate ÷ 12
Assumptions & limitations
- Results are rounded for display.
Frequently asked questions
Is it better to invest the extra money?
Paying down a 6.5% mortgage is like a guaranteed 6.5% return. Whether investing beats it depends on your risk tolerance and tax situation.