Every extra dollar applied to principal removes the future interest that dollar would have generated for the remaining term. On a 30-year loan, that compounding effect is enormous.
An extra $200 a month on a $300,000 loan at 6.5% can shorten the term by roughly 6 years and save tens of thousands in interest. The exact number depends on your rate and balance — but the direction is always the same.
If cash flow is tight, even one extra payment per year (or switching to bi-weekly payments) creates a similar effect with less monthly strain.
Key takeaways
- Extra principal saves all future interest on that dollar.
- Bi-weekly payments add one full payment per year automatically.
- Always direct extra payments to principal — confirm with your lender.
Apply it with these calculators
Mortgage Calculator
Estimate monthly mortgage payments, interest and amortization schedules.
Extra Payment Payoff
Calculate exactly how much faster — and cheaper — extra principal makes your loan.
Biweekly Payment Calculator
See how biweekly mortgage payments cut years off your loan.
Amortization Calculator
Full payoff schedule with principal vs interest, charts, extra payments, and PDF/CSV export.
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Written and reviewed by
Keiron Brown, Psy.D.
Founder & Lead Educator, CalculatingWealth
Keiron Brown, Psy.D., is a clinical psychologist and the founder of Relationale LLC, which publishes CalculatingWealth. His doctorate is in psychology, not finance: he is not a registered investment adviser, accountant, or attorney, and nothing here is financial, investment, tax, or legal advice. His work here focuses on financial education, critical thinking, and decision-making — helping people understand the math behind money so they can plan with clarity and confidence. He writes about wealth building, retirement planning, investing literacy, budgeting, and the behavioral patterns that shape long-term financial outcomes.
Editorial standards: All educational content on CalculatingWealth is reviewed for accuracy, sourced from primary references where applicable (IRS, SSA, Federal Reserve, BLS), and updated when rules or rates change. Content is for educational and informational purposes only and does not constitute financial, investment, tax, or legal advice.
Not advice: Keiron Brown is not a registered investment adviser, broker-dealer, certified public accountant, enrolled agent, attorney, or licensed insurance producer. His work is educational in nature. See our full disclaimer.