One extra payment a year shortens your loan by roughly two to three years and saves tens of thousands in interest

Making one additional mortgage payment annually—whether as a lump sum or split across months—accelerates payoff on a 30-year mortgage to somewhere between 27 and 28 years. The exact timeline depends on your loan balance, interest rate, and when in the year you make the payment. A borrower with a $300,000 mortgage at 6.5% interest who makes one extra $1,500 payment per year will pay off the loan roughly 2.5 years faster and save approximately $60,000 to $80,000 in total interest, compared to making only the scheduled 360 payments.

The math works because every dollar of that extra payment goes directly to principal—the amount you actually owe—rather than being split between principal and interest the way your regular monthly payment is. Since interest is calculated on the remaining balance, paying down principal faster means you owe less money for the bank to charge interest on each month going forward. The earlier in the loan you make extra payments, the more interest you prevent from accruing.

Key Takeaways

  • One extra mortgage payment per year typically shortens a 30-year loan by 2 to 3 years and reduces total interest paid by $50,000 to $100,000, depending on your loan size and rate.
  • The entire extra payment reduces your principal balance, not split between principal and interest like your regular monthly payment.
  • Making the extra payment early in the loan year produces more savings than making it late, because the lower balance accrues less interest for the remaining months.
  • You must instruct your lender to apply the extra payment to principal; some servicers will hold it in escrow or apply it to the next month's payment unless you specify otherwise.
  • One extra payment per year is easier to sustain than biweekly payment plans, and produces nearly identical results for most borrowers.

How the math changes with different loan sizes and rates

The dollar amount you save depends on both your interest rate and your remaining loan balance. A borrower with a $200,000 mortgage at 5% interest making one extra $1,000 payment annually will save roughly $35,000 to $45,000 in interest and shorten the loan by about 2.5 years. The same borrower at 7% interest saves closer to $55,000 to $65,000 and still shortens the loan by roughly 2.5 years—higher rates mean more interest accrues each month, so paying principal faster saves more dollars overall.

The size of your extra payment matters less than the consistency. A $1,500 extra payment saves more than a $500 extra payment, but the relationship is not linear. Your first extra payment produces the largest interest savings because it reduces the balance at the point when the most interest remains to be charged. Your tenth extra payment produces smaller savings because the remaining balance is already lower. This is why the total savings from one extra payment per year compounds over time—you are preventing interest from accruing on that principal reduction for the entire remaining life of the loan.

When to make the extra payment for maximum impact

Making your extra payment in January produces more savings than making it in December, because the lower balance sits for the entire year and accrues less interest each month. If you make a $1,500 extra payment in January, that $1,500 reduces your balance for all 12 months of interest calculations. If you make the same payment in November, it reduces your balance for only 2 months before the year ends and a new interest cycle begins.

Some borrowers split the extra payment into 12 monthly installments of roughly $125 (if their regular payment is $1,500), which is mathematically equivalent to making one lump sum in January—the principal reduction happens gradually but consistently. Others make the full extra payment once per year, often when they receive a tax refund or bonus. Both approaches work; the key is that the money goes to principal, not to escrow or the next month's regular payment.

How to instruct your lender to apply the extra payment correctly

Contact your mortgage servicer in writing—email, online portal, or certified mail—and specify that you want the extra payment applied to principal only, not held in escrow or credited to your next regular payment. Many servicers have a default setting that treats extra payments as prepayment of the next month's scheduled payment, which delays the principal reduction by 30 days and costs you interest savings. Some servicers require a separate check or payment method marked "principal only" to process it correctly.

Ask your servicer for written confirmation that they received the instruction and will apply future extra payments to principal. Keep records of each extra payment you make—the date, amount, confirmation number, and the servicer's written acknowledgment. If you refinance or your loan is sold to a new servicer, you will need to repeat this instruction with the new company, because the directive does not transfer automatically.

Comparing one extra payment to biweekly payment plans

A biweekly payment plan—where you pay half your monthly mortgage every two weeks instead of the full amount once per month—produces nearly identical results to making one extra payment per year. Over 26 biweekly periods, you make 13 half-payments, which equals one extra full payment annually. The total interest saved and timeline shortened are roughly the same, but biweekly plans require you to change your payment schedule with your servicer and may involve setup fees of $200 to $500.

One extra annual payment is simpler to manage if you receive a bonus or tax refund once per year—you make a single transaction rather than restructuring your entire payment schedule. It also avoids fees. The trade-off is that you must remember to make the extra payment; biweekly plans are automatic once set up. For most borrowers, one extra payment per year is the easier path to the same destination.

What happens to your payment schedule after extra payments

Your regular monthly payment amount does not change when you make extra principal payments. Your servicer will recalculate your loan payoff date and the total interest you will owe, but your monthly payment stays the same unless you refinance or modify your loan. This means the extra payments accumulate—each one reduces the remaining balance, so the next month's interest calculation is based on a smaller amount, and more of your regular payment goes to principal instead of interest.

Over time, this creates a compounding effect. Your first extra payment saves you interest for 29+ years. Your second extra payment saves you interest for 28+ years. By the time you have made 10 extra payments, you have reduced the remaining balance significantly enough that your regular monthly payment is now split much more heavily toward principal than it was at the start of the loan. This acceleration is why extra payments made early in the loan produce the largest total savings.

When extra payments make sense and when they do not

Extra mortgage payments make financial sense if your interest rate is higher than the return you could earn on the same money in a savings account or investment. If your mortgage rate is 6.5% and a high-yield savings account pays 4.5%, the may provide 2% difference favors paying down the mortgage. If your mortgage rate is 3% and you can earn 5% in a money market fund, investing the extra money produces better returns than paying principal.

Extra payments also make sense if you have no high-interest debt (credit cards, personal loans) and have built an emergency fund of three to six months of expenses. Paying down a mortgage faster is a lower priority than eliminating 18% credit card interest or protecting yourself against job loss. If you are uncertain whether you can sustain one extra payment per year without affecting your ability to save for emergencies or other goals, start with a smaller amount—$500 or $250 per year—and increase it as your financial situation improves.

Frequently Asked Questions

Does making one extra payment a year affect my credit score?

No. Extra principal payments reduce your loan balance and may slightly improve your credit over time by lowering your debt-to-income ratio, but they do not directly affect your credit score. Your score is based on payment history, credit utilization, and age of accounts—not on how quickly you pay down a loan.

Can I make extra payments if my mortgage is in an escrow account?

Yes. Escrow accounts hold money for property taxes and insurance, separate from your principal and interest payment. Extra principal payments go directly to the loan balance and do not affect escrow. You still instruct your servicer to apply the extra payment to principal only.

What if I want to stop making extra payments later?

You can stop at any time. Your regular monthly payment remains the same, and you simply do not make the extra payment that year. The principal reduction you already made stays in place—you do not owe it back. Your loan will take longer to pay off than if you had continued, but you have already saved interest on the years you did make extra payments.

Does one extra payment a year work the same way for a 15-year mortgage?

Yes, but the timeline impact is smaller because you are already paying off the loan faster. One extra payment on a 15-year mortgage shortens it by roughly 1 to 1.5 years and saves less total interest in dollars, because the loan balance is paid down more quickly to begin with. The math is the same; the starting point is different.

Should I make extra payments if I am planning to sell or refinance soon?

Only if you plan to stay in the home long enough to recoup the interest savings. If you will sell within two to three years, the extra payments may not save enough interest to justify the money you could have kept liquid. If you plan to refinance, extra payments reduce your loan balance, which lowers your new loan amount and total interest on the refinanced loan—so they still provide value, just in a different form.