One extra payment a year saves roughly 4 to 5 years of payments and tens of thousands in interest

A single extra mortgage payment made once per year shortens a 30-year loan by approximately 4 to 5 years. The exact savings depend on your loan balance, interest rate, and how far into the loan you are. On a $300,000 mortgage at 6.5% interest, one extra payment per year saves roughly $60,000 to $80,000 in total interest paid over the life of the loan.

The reason one payment makes this much difference is that mortgage interest compounds daily. When you pay down principal faster, you reduce the amount that interest accrues on in future months. Early in the loan, most of your payment goes to interest; extra principal payments hit hardest then, because they stop interest from accumulating on that amount for the remaining 30 years.

The savings are not linear. Your first extra payment saves more than your tenth, because the loan balance is higher early on. But the cumulative effect is substantial—one payment per year, made consistently, reshapes the entire loan timeline.

Key Takeaways

  • One extra mortgage payment per year typically shortens a 30-year loan by 4 to 5 years and reduces total interest paid by $60,000 to $80,000 on a $300,000 loan at 6.5% interest.
  • The timing of the extra payment matters: paying it early in the year or early in the loan cycle produces larger savings than paying it late.
  • You must direct the extra payment to principal, not let the lender apply it to the next month's payment—confirm this in writing with your servicer.
  • Making one extra payment per year is easier to sustain than biweekly payments, because you can save the money over 12 months rather than restructuring your entire paycheck.

How the math works: interest, principal, and time

A mortgage payment is split between principal (the amount borrowed) and interest (the cost of borrowing). Early in the loan, interest takes 80 to 90% of each payment. If you make a regular payment, you are mostly paying interest and barely touching principal.

When you make an extra payment and direct it entirely to principal, you reduce the loan balance immediately. That smaller balance means less interest accrues in the next month. Over 30 years, this compounds: less principal means less interest, which means more of your regular payments go to principal in future months, which means even less interest.

On a $300,000 loan at 6.5% over 30 years, your regular monthly payment is approximately $1,896. One extra payment of $1,896 applied to principal reduces the total interest you will pay by roughly $60,000 to $80,000, depending on when in the year you make it. If you make it in January, the savings are larger than if you make it in December, because the reduced balance has 11 more months to compound.

When you make the payment matters more than you might think

The timing of your extra payment affects how much interest you save. A payment made in January has 11 more months to reduce the balance and stop interest from accruing. A payment made in December has almost no time to work before the year ends and the loan continues at the original pace.

For maximum savings, make your extra payment as early in the year as possible—ideally in January or February. This gives the reduced principal balance the longest time to compound savings through the rest of the year and beyond.

If you cannot make the payment early, making it late is still better than not making it at all. Even a December payment saves money; it just saves less than an earlier one would have.

The critical step: making sure the payment goes to principal

Many mortgage servicers will automatically apply an extra payment to your next month's regular payment instead of to principal. This defeats the purpose. You must explicitly instruct your servicer to apply the extra payment to principal only.

Call your servicer or log into your account and look for an option to make a "principal-only payment" or "extra principal payment." Some servicers require you to send a written request with your payment; others allow you to specify it online. Do not assume the servicer will figure it out. Confirm in writing—email or a printed statement—that your extra payment was applied to principal, not to next month's payment.

If your servicer applies it incorrectly, contact them immediately and ask for the payment to be reapplied. This is a common mistake and servicers can correct it, but only if you catch it.

One payment per year versus biweekly payments

Some borrowers make biweekly payments (half the monthly payment every two weeks) instead of one monthly payment. Over a year, this adds up to 13 monthly payments instead of 12—the same as one extra payment. The interest savings are similar, but the mechanics are different.

Biweekly payments require restructuring your paycheck or budget to align with a two-week cycle. One extra payment per year is simpler: you save the money over 12 months and make one lump-sum payment. For most people, one annual payment is easier to sustain and less likely to be missed.

If your servicer charges a fee to set up biweekly payments, one annual extra payment avoids that cost entirely. Check whether your servicer charges before committing to either strategy.

How much you save depends on your loan details

The savings from one extra payment vary based on three factors: the loan balance, the interest rate, and how far into the loan you are.

A higher interest rate means more interest accrues each month, so an extra payment saves more. A $300,000 loan at 7.5% interest saves more from one extra payment than the same loan at 5.5% interest. A larger loan balance also means larger savings in absolute dollars, though the percentage savings remain similar.

The stage of the loan matters too. An extra payment made in year 1 saves more than an extra payment made in year 20, because the balance is higher and the interest is compounding for longer. If you are 10 years into a 30-year loan, one extra payment still shortens the loan and saves money, but the total savings are smaller than if you had made that payment in year 1.

Use a mortgage calculator that accepts extra payments to see the exact savings for your loan. Enter your balance, rate, remaining term, and the amount of your extra payment. The calculator will show you the new payoff date and total interest saved.

What happens if you stop making extra payments

If you make extra payments for a few years and then stop, you still keep the benefit of the years you did pay extra. Your loan is shorter than it would have been, and you have paid less interest. You do not have to make extra payments every single year to see a benefit.

However, the savings are cumulative. One extra payment saves 4 to 5 years; two extra payments save roughly 8 to 10 years (not exactly double, because the second payment is made on a smaller balance). If you can sustain the extra payment consistently, the long-term savings are much larger than if you make it sporadically.

If your financial situation changes and you cannot make extra payments, do not feel obligated to continue. Your regular monthly payment is all you are required to make. Extra payments are a tool to use when you can afford them, not a commitment you cannot break.

Frequently Asked Questions

Can I make multiple extra payments in one year instead of spreading them out?

Yes. Making two or three extra payments in one year saves more than making one. The total savings depends on the amount and timing, but the principle is the same: more principal paid down means less interest accrues. Spread them throughout the year if possible to maximize the compounding effect, but even making them all at once is better than not making them.

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

No. Extra payments reduce your loan balance and show consistent payment history, both of which are positive for credit. Your score may actually improve slightly over time as your loan-to-value ratio improves and your payment history lengthens.

What if I have a variable-rate mortgage—does one extra payment still save money?

Yes, but the savings are harder to predict. With a variable rate, your interest rate changes at set intervals, so the total interest you will pay over the life of the loan is unknown. An extra payment still reduces your principal balance and saves interest during the period when the current rate is in effect. The long-term savings depend on what rates do in the future.

Is it better to make one extra payment per year or to refinance to a shorter loan term?

One extra payment per year is simpler and costs nothing. Refinancing to a 15-year loan instead of 30 years increases your monthly payment significantly and involves closing costs and a new application. If you can afford the higher payment and want to lock in a shorter term, refinancing works. If you want to shorten the loan without increasing your monthly payment, extra payments are the better choice.

What if my mortgage servicer will not let me make principal-only payments?

Most servicers allow it, but a few older loan documents or servicer policies may restrict it. If yours does, ask in writing why and request an exception. If they refuse, you can still make extra payments—they will just be applied to your next month's payment instead of principal. This is less efficient but still reduces the total interest you pay over time. Consider switching servicers if this is a major concern.