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

When you make one additional mortgage payment per year—whether as a lump sum or split into monthly amounts—that money goes directly to principal. Because interest is calculated on the remaining balance, lowering the balance faster means you pay less interest over the life of the loan. On a 30-year mortgage, one extra payment per year typically cuts 4 to 8 years off the loan term and saves between $40,000 and $80,000 in total interest, depending on your loan amount and rate. The exact savings depend on your specific loan balance, interest rate, and how early in the loan you start.

The math works because of how mortgage payments are structured. In the early years, most of your payment goes to interest and only a small portion to principal. By paying extra principal, you skip over months or years where that payment would have been mostly interest. Each extra payment compounds this effect—you pay interest on a smaller balance going forward, which means more of your regular payments go to principal instead of interest.

Key Takeaways

  • One extra mortgage payment per year reduces your loan term by roughly 4 to 8 years on a standard 30-year mortgage.
  • The extra payment goes entirely to principal, which lowers the balance faster and reduces the total interest you pay over the life of the loan.
  • You can make one extra payment as a single annual lump sum, split it into monthly additions, or pay biweekly to achieve the same result.
  • The savings are largest when you start early in the loan term, because interest compounds over decades.
  • Before making extra payments, confirm your loan has no prepayment penalty and that your lender will credit the payment to principal, not to future payments.

How the math works: principal, interest, and compounding

A standard 30-year mortgage on $300,000 at 6.5% interest costs roughly $2,000 per month. Of that first payment, about $1,625 goes to interest and only $375 to principal. If you make one extra $2,000 payment toward principal in year one, you have immediately reduced the balance by $2,000. That $2,000 reduction means every future payment will have slightly less interest baked in and slightly more going to principal.

Over 30 years, this compounds. The extra payment in year one saves interest not just on that year, but on every year after it. By year 10, you will have paid off roughly 15 years' worth of principal through a combination of regular payments and extra payments. The loan accelerates from there. What would have taken 30 years now takes 22 to 26 years, depending on when you started and how consistently you made extra payments.

The earlier you start, the larger the effect. An extra payment in year one saves more total interest than an extra payment in year 15, because the balance is higher and the remaining loan term is longer. This is why making extra payments as soon as you can—even if you can only afford one per year—produces the biggest long-term savings.

Three ways to structure one extra payment per year

Annual lump sum: Save up and make one full extra payment once per year, usually in a month when you have bonus income or a tax refund. This is the simplest method if you have irregular income or prefer to make one deliberate decision per year. Make sure to specify in writing or through your lender's online portal that the payment should go to principal, not to next month's payment.

Monthly additions: Divide one extra annual payment by 12 and add that amount to your regular mortgage payment each month. If your mortgage is $2,000 and one extra payment is $2,000, you would pay $2,167 per month ($2,000 + $167). This spreads the extra payment across the year and makes it feel like a smaller adjustment to your budget. Over 12 months, you have made one full extra payment without a large single outlay.

Biweekly payments: Some lenders allow you to pay half your monthly mortgage every two weeks instead of paying the full amount once per month. Because there are 26 biweekly periods in a year and only 12 months, this method results in 13 half-payments per year—which equals one extra full payment. Check whether your lender charges a fee to set up biweekly payments; some do, and the fee can offset part of the savings.

What to confirm with your lender before you start

Not all mortgages allow extra principal payments without penalty. Before you make any extra payment, contact your lender or review your loan documents for a prepayment penalty—a fee charged if you pay off the loan faster than the agreed schedule. Prepayment penalties are less common now than they were 15 years ago, but they still exist on some loans, particularly those sold to investors or loans with below-market interest rates.

Also confirm that your lender will credit the extra payment to principal, not to your next month's regular payment. Some lenders default to applying extra money to future payments, which defeats the purpose. You may need to write "apply to principal" on the check, include a note with an online payment, or call the lender to specify. Get written confirmation that the payment was applied correctly, especially for the first extra payment.

If your loan is held by a servicer (the company that collects your payment) rather than the original lender, the servicer's website should show an option to make extra principal payments. If you do not see one, call and ask how to make a principal-only payment. Some servicers require a separate transaction or a specific form.

The real savings over 30 years

On a $300,000 mortgage at 6.5% over 30 years, the total interest paid is roughly $377,000. With one extra $2,000 payment per year, the loan is paid off in approximately 24 years instead of 30, and total interest drops to roughly $310,000. That is a savings of $67,000 in interest and 6 years of payments eliminated.

The savings scale with the loan amount. On a $500,000 mortgage at the same rate, one extra payment per year saves roughly $110,000 in interest. On a $200,000 mortgage, the savings are roughly $45,000. The percentage savings is similar across loan sizes, but the dollar amount grows with the principal.

These numbers assume you make the extra payment consistently every year and that you do not refinance or take out a new loan. If you refinance, the clock resets—you start a new loan term, and the benefit of your earlier extra payments is locked in, but you do not continue to accelerate the payoff unless you make extra payments on the new loan as well.

When extra payments make sense and when they do not

Making extra mortgage payments is most useful if your interest rate is above 5%, you plan to stay in the home for at least 5 more years, and you have no high-interest debt (credit cards, personal loans) that you are still paying down. If you are carrying credit card debt at 18% interest, paying down that debt first produces a larger return on your money than paying extra on a 4% mortgage.

Extra payments also make less sense if you have a very low interest rate (below 3%) and a long time horizon. The opportunity cost of putting that money into investments or a high-yield savings account may exceed the interest you save on the mortgage. However, if you simply want to own your home free and clear faster and have the cash available, the psychological benefit of shortening the loan term often outweighs the math.

If you are uncertain whether you will stay in the home long enough to recoup the benefit, calculate the break-even point. On most mortgages, one extra payment per year breaks even (the interest saved exceeds any transaction costs) within 3 to 5 years. If you plan to move or refinance within that window, the savings may be minimal.

Frequently Asked Questions

Can I make extra payments without paying a penalty?

Most mortgages issued in the past 10 years have no prepayment penalty, but some do. Check your loan documents or call your lender to confirm. If a penalty exists, it is usually only charged if you pay off the entire loan early, not if you make extra monthly or annual payments.

What if I can only afford one extra payment every other year?

One extra payment every two years still saves money—it just saves less than one per year. The benefit is proportional to how many extra payments you make. Even one extra payment early in the loan term produces meaningful savings over 30 years.

Does making extra payments hurt my credit score?

No. Paying extra on your mortgage does not lower your credit score. It may slightly improve your score over time because it lowers your debt-to-income ratio and shows consistent on-time payment history.

What happens to my extra payment if I refinance?

The principal you paid down stays paid down—it reduces the balance of your current loan. When you refinance, you take out a new loan for the remaining balance. The interest savings from your extra payments on the old loan are locked in, but you start fresh with a new loan term on the new mortgage.

Is it better to invest the money instead of paying extra on my mortgage?

That depends on investment returns and your interest rate. If you can reliably earn more in investments than your mortgage interest rate, investing may produce larger long-term wealth. However, paying extra on your mortgage is may provide to save you that interest rate, whereas investment returns are not may provide.