Mortgage Acceleration Calculator
Even small extra payments can shave years off your mortgage and save tens of thousands in interest. Enter your loan details to see the impact.
The Compounding Power of Extra Payments
Mortgage interest is front-loaded. In the early years, most of your payment goes to interest, not principal. An extra $200 in year one might save you $600 in interest over the life of the loan because it prevents that principal from accruing interest for 29 more years. The same $200 in year 25 saves much less because there's less time for interest to compound.
That's why starting extra payments early matters so much. Even if you can only afford $50 or $100 extra now, do it. You can always increase it later. The savings from those early payments far exceed what you'd save by waiting five years and then paying $300 extra.
Every dollar of extra payment reduces your principal immediately. Less principal means less interest next month, which means more of your regular payment goes to principal, which accelerates payoff even faster. It's a virtuous cycle that builds momentum over time.
Common Mortgage Acceleration Strategies
Biweekly payments are a popular trick. Instead of paying once a month, you pay half your mortgage every two weeks. Because there are 52 weeks in a year, you make 26 half-payments, which equals 13 full payments instead of 12. That extra payment each year can cut 5-7 years off a 30-year mortgage.
Rounding up works too. If your payment is $1,487, round it to $1,500. That extra $13 doesn't hurt your budget, but it adds up to $156 per year in extra principal. Over 30 years, that small change can save $15,000 to $20,000 in interest.
Some borrowers make one large extra payment per year—maybe from a tax refund, bonus, or windfall. Applying $3,000 once a year to principal has nearly the same effect as $250 per month. The timing matters slightly (monthly is marginally better), but the key is consistency. Pick a strategy you can sustain.
When Acceleration Doesn't Make Sense
If your mortgage rate is below 4%, you might be better off investing extra cash instead of paying down the loan. Historically, diversified stock portfolios return 8-10% annually. If you're paying 3.5% on your mortgage but could earn 8% in an index fund, the math favors investing.
Also consider high-interest debt. If you have credit cards at 18% or a car loan at 7%, pay those off before accelerating a 6% mortgage. Always eliminate the highest-rate debt first—it's guaranteed savings with the biggest impact.
Emergency funds come before acceleration too. If you don't have 3-6 months of expenses saved, build that cushion first. You can't pull equity out of your house instantly if you lose your job. Liquidity and safety trump interest savings when your financial foundation isn't secure yet.
Frequently Asked Questions
How much can $100/month extra save?
On a $250,000 mortgage at 6% over 30 years, an extra $100/month saves about $42,000 in interest and cuts 5 years off the loan. The exact savings depend on your rate and balance.
Should I make extra payments or invest the money?
If you can earn more in investments than your mortgage rate, investing might be better. But paying off your mortgage is a guaranteed return equal to your interest rate, with zero risk. Many people split the difference.
Do extra payments go toward principal?
Yes, as long as you specify that the extra amount should be applied to principal. Some lenders default to applying overpayments to the next month's payment instead. Always indicate 'apply to principal' when making extra payments.
Is there a penalty for paying off my mortgage early?
Most mortgages originated after 2010 have no prepayment penalties. Check your loan documents or call your lender. If there is a penalty, it usually expires after 3-5 years.
Should I make one big payment or spread it out monthly?
Monthly extra payments save more interest because they reduce the principal sooner, which means less interest accrues each month. A lump sum once a year helps, but monthly is more efficient.