One extra payment a year cuts roughly 4 to 5 years off a 30-year mortgage and saves between $40,000 and $80,000 in interest, depending on your loan size and rate
The exact savings depend on three things: your loan balance, your interest rate, and when in the loan you make the extra payment. A borrower with a $300,000 mortgage at 6% interest who makes one extra $1,800 payment per year will pay off the loan around year 25 instead of year 30, saving approximately $60,000 in total interest. Someone with a $200,000 mortgage at 4% interest saves roughly $25,000 to $30,000 over the life of the loan with the same strategy.
The savings are larger when you make the extra payment early in the loan, because more of each regular payment goes toward principal in the early years. An extra payment in year 1 saves more interest than an extra payment in year 15, even though the payment amount is the same. The interest rate matters too: a borrower at 7% saves more in absolute dollars than a borrower at 3%, because the interest charges are higher to begin with.
Key Takeaways
- One extra annual payment typically shortens a 30-year mortgage by 4 to 5 years and reduces total interest paid by $40,000 to $80,000, though the exact amount depends on your loan balance and rate.
- The earlier you make extra payments, the more interest you save, because principal payments in early years prevent years of compounding interest.
- Making the extra payment monthly in smaller chunks ($150 instead of $1,800 once a year) saves slightly more interest because the money reduces your balance sooner.
- Extra payments go directly to principal and do not affect your monthly payment amount or your loan term unless you formally request a modification.
How the math works: principal, interest, and time
A standard 30-year mortgage splits each payment between principal (the amount borrowed) and interest (the cost of borrowing). Early in the loan, most of your payment covers interest. By year 20, the split has flipped. An extra payment of $1,800 goes entirely to principal because you are not making a scheduled payment—you are reducing what you owe.
When you reduce the principal balance, you reduce the amount the lender charges interest on for the remaining life of the loan. On a $300,000 loan at 6%, that $1,800 payment prevents roughly $1,080 in interest charges over the remaining 30 years (6% of $1,800 per year for 30 years, simplified). In reality, the math is more complex because the balance shrinks each month, but the principle is the same: less principal means less total interest.
The timing of the extra payment matters because of how compound interest works. If you make the extra payment in month 1, it reduces your balance for all 360 months. If you make it in month 180, it reduces your balance for only 180 months. That is why one lump-sum payment early in the loan saves more than the same payment made later, even though the dollar amount is identical.
Comparing one lump-sum payment versus monthly extra payments
Some borrowers make one extra payment at the end of the year. Others split it into monthly chunks—an extra $150 per month instead of $1,800 in December. The monthly approach saves slightly more interest because the money reduces your balance sooner and compounds over a longer period.
The difference is not dramatic. On a $300,000 mortgage at 6%, making $150 extra payments monthly instead of one $1,800 payment annually might save an additional $2,000 to $3,000 in interest over the life of the loan. The advantage of the monthly approach is that it is easier to budget and harder to skip. The advantage of the annual approach is that it requires only one decision and one transaction per year.
Some lenders allow you to set up automatic extra principal payments through your online account. Others require you to send a separate check or make a manual online transfer and specify that the money should go to principal, not to next month's payment. Check your loan documents or call your servicer to confirm how they handle extra payments and whether there are any fees.
What changes and what does not when you make extra payments
Extra principal payments do not lower your monthly payment. Your loan agreement specifies a payment amount, and that amount stays the same unless you formally refinance or modify the loan. What changes is how much of each payment goes to principal versus interest, and how many months you will be making payments.
If you make extra payments, your loan will be paid off sooner—possibly years sooner. Your lender will send you a new amortization schedule showing the updated payoff date. Some borrowers use this to their advantage: they make extra payments for several years, then stop when the loan is nearly paid off. Others make one extra payment per year indefinitely and watch the payoff date move up month by month.
Extra payments also do not affect your credit score or your loan terms. They are straightforward a way to reduce the total amount of interest you pay. If you have other high-interest debt—credit cards, for example—paying down that debt first usually saves more money than making extra mortgage payments, because credit card interest rates are typically much higher than mortgage rates.
Real-world examples: three different scenarios
| Loan Amount | Interest Rate | Monthly Payment | Extra Annual Payment | Payoff Shortened By | Interest Saved |
|---|---|---|---|---|---|
| $200,000 | 4% | $955 | $955 | 3–4 years | $25,000–$30,000 |
| $300,000 | 6% | $1,799 | $1,799 | 4–5 years | $55,000–$65,000 |
| $400,000 | 7% | $2,661 | $2,661 | 4–5 years | $80,000–$100,000 |
These figures assume the extra payment is made in the first year and continues annually for the life of the loan. The actual savings will vary based on when you start, how consistently you make the extra payments, and changes in your loan balance if you refinance or take out a home equity line of credit.
When extra payments make sense and when they do not
Extra mortgage payments make the most sense if you have stable income, an emergency fund with three to six months of expenses, and no high-interest debt. They also make sense if your mortgage rate is higher than the return you could earn by investing the money elsewhere. At current rates, a 6% mortgage and a 4% savings account or bond fund mean the mortgage is the better place to put extra money.
Extra payments make less sense if you are carrying credit card debt at 18% to 22% interest, because paying that down first saves far more money. They also make less sense if you are uncertain about your income or if you might need the cash in the next few years. Mortgage payments are flexible in a crisis—you can ask for forbearance or a loan modification—but the money you send in is gone.
Some borrowers use extra payments as a psychological tool: they know they will not invest the money wisely, so they force themselves to build equity faster by paying down the mortgage. That is a valid reason, even if the math does not show it as the optimal financial move. The best financial strategy is the one you will actually follow.
How to set up extra payments with your lender
Contact your mortgage servicer—the company that collects your monthly payment—and ask how they accept extra principal payments. Most will let you pay online, by phone, or by mail. Some require you to write "principal only" on the check or specify in the online payment form that the extra amount should not be applied to next month's payment.
Ask whether there are any fees for extra payments. Most servicers do not charge, but some older loan agreements or certain loan types may have prepayment penalties. These are rare on mortgages originated after 2010, but it is worth confirming. Also ask whether you can set up automatic extra payments or whether you need to make them manually each time.
Keep records of your extra payments. Your servicer should reflect them on your statement and in your online account, but mistakes happen. If you notice that an extra payment was applied to next month's payment instead of principal, contact the servicer when ready and ask them to correct it.
Frequently Asked Questions
Does making one extra payment a year actually shorten the loan by a full year?
No. One extra payment per year typically shortens a 30-year mortgage by 4 to 5 years total, not by 1 year. The exact reduction depends on your interest rate and loan balance. A higher rate or larger balance means the extra payment saves more interest and shortens the loan more.
What if I make extra payments for a few years and then stop?
The extra payments you made will still reduce your total interest and shorten your payoff date. If you make extra payments for 5 years and then stop, you will still pay off the loan sooner than if you had never made them. The payoff date will not move back up—it will straightforward stop moving forward.
Is it better to make extra mortgage payments or invest the money?
It depends on your interest rate and investment returns. If your mortgage is at 6% and you can reliably earn 7% or more in the stock market, investing is mathematically better. If your mortgage is at 7% and you can only earn 4% in bonds, paying down the mortgage is better. Most people overestimate their investment returns, so paying down the mortgage is the safer choice.
Can I make extra payments if I have a variable-rate mortgage?
Yes. Extra principal payments work the same way on variable-rate mortgages as on fixed-rate mortgages. The payment reduces your balance when ready, and the interest savings compound over time. When your rate adjusts, your new payment will be calculated on the lower balance.
Will extra payments hurt my credit score?
No. Extra payments have no negative effect on your credit score. They reduce your loan balance, which can slightly improve your credit over time by lowering your credit utilization ratio (the amount you owe compared to your credit limits), though the effect is small for mortgages.