One extra payment per year shortens your loan by 4 to 7 years, depending on your rate and loan term
A single extra mortgage payment made once a year goes almost entirely toward principal because you are bypassing the monthly interest charge. That principal reduction compounds: it lowers the balance that future interest accrues on, which means less interest paid overall and a faster payoff date. The exact number of years saved depends on your interest rate, your original loan term, and how early in the loan you start making extra payments.
On a 30-year mortgage at 6 percent interest, one extra payment per year typically saves 4 to 5 years. On the same loan at 4 percent, you save roughly 3 to 4 years. At 8 percent, you save closer to 6 to 7 years. The higher your rate, the more interest you are paying monthly, so the impact of extra principal payments is larger. Starting early matters: an extra payment in year 1 saves more time than the same payment in year 15, because the principal reduction compounds for longer.
Key Takeaways
- One extra mortgage payment per year typically saves 4 to 7 years off a 30-year loan, with the exact number depending on your interest rate and when you start.
- The extra payment goes almost entirely to principal because you are not paying a monthly interest charge, so the impact is much larger than a regular monthly payment split between interest and principal.
- Higher interest rates mean more interest paid each month, so extra principal payments have a bigger effect on total interest saved and payoff time.
- Making extra payments early in the loan saves more time than making them late, because the principal reduction compounds over more years.
How the math works: interest versus principal
A regular monthly mortgage payment is split between interest and principal. Early in the loan, most of your payment goes to interest. On a $300,000 loan at 6 percent over 30 years, your monthly payment is about $1,799. In month 1, roughly $1,500 goes to interest and only $299 to principal. By month 180 (year 15), the split is closer to $750 interest and $1,049 principal.
When you make an extra payment once a year, that entire payment (minus any fees, which are rare) goes to principal. You are not paying a monthly interest charge on top of it. That $1,799 extra payment reduces your balance by $1,799 instead of $299. The next month's interest accrues on a lower balance, so you pay slightly less interest that month. Over 30 years, this compounds into years of time saved.
Comparing one extra payment to biweekly payments
Some borrowers make biweekly payments (every two weeks) instead of monthly payments. Over a year, biweekly payments add up to 26 half-payments, which equals 13 full monthly payments instead of 12. That is roughly the same as one extra payment per year, so the time saved is similar: 4 to 7 years depending on your rate.
The difference is consistency. Biweekly payments happen automatically if your lender or employer supports them. One extra payment per year requires you to remember to make it and have the cash available. Some borrowers split the difference: they make one extra payment every six months, or they round up their regular payment by $100 or $200 each month. All of these approaches save time, but the total time saved depends on how much extra principal you send in total, not on the method.
Total interest saved over the life of the loan
On a $300,000 loan at 6 percent over 30 years, you pay roughly $215,000 in interest total. Making one extra payment per year reduces that to roughly $155,000 to $165,000 in interest, depending on exactly when in the year you make the payment. That is a savings of $50,000 to $60,000 in interest.
The interest saved is larger on higher-rate loans and smaller on lower-rate loans. A $300,000 loan at 4 percent costs roughly $115,000 in interest over 30 years; one extra payment per year saves roughly $25,000 to $30,000. At 8 percent, the same loan costs roughly $340,000 in interest; one extra payment per year saves roughly $80,000 to $100,000. The higher your rate, the more you benefit from extra principal payments.
When to make the extra payment for maximum impact
Making the extra payment early in the year (January or February) saves slightly more time than making it late in the year (November or December), because the principal reduction compounds for longer. The difference is small—usually a few months over the life of the loan—but it exists. If you have the cash available early, send it in early.
Making the extra payment early in the loan (years 1 to 10) saves more time than making it late (years 20 to 30). An extra payment in year 1 might save 7 years; the same payment in year 25 might save only 1 year. This is because the principal reduction compounds over more years. If you can only afford extra payments for part of your loan term, prioritize the early years.
How to structure one extra payment per year
The simplest method is to save one-twelfth of your monthly payment each month and send it in as a lump sum once a year. If your payment is $1,800, you set aside $150 per month and send $1,800 in extra principal around the same time each year. Make sure your lender applies it to principal, not to next month's payment. Some lenders do this automatically; others require you to specify in writing or through your online account.
Another method is to round up your monthly payment. If your payment is $1,799, pay $1,900 each month. That extra $101 per month adds up to roughly $1,212 per year, which is slightly more than one full payment. Over time, this saves a bit more time than exactly one payment per year. The advantage is that it happens automatically with your regular payment; the disadvantage is that you need the extra cash every month, not just once a year.
What to watch out for
Some lenders charge a fee for extra payments or require a minimum payment amount. This is rare, but check your loan documents or call your lender before you start. If there is a fee, it may not be worth making extra payments unless the fee is very small (under $25).
Make sure your extra payment is applied to principal, not to next month's regular payment or to escrow (property taxes and insurance). When you send in the payment, include a note or use your online account to specify "apply to principal" or "prepayment." If you are unsure, call your lender and confirm that the payment was applied correctly on your next statement.
If you have a variable-rate mortgage (ARM), extra payments still save time and interest, but your rate may change, which changes the calculation. If your rate rises, the benefit of extra payments increases. If it falls, the benefit decreases. The principle is the same: extra principal reduces your balance and the interest that accrues on it.
Frequently Asked Questions
Can I make extra payments without penalty?
Most mortgages allow extra payments without penalty, but some older loans or loans sold to certain investors may have prepayment penalties. Check your loan documents or call your lender. If there is a penalty, it usually expires after 3 to 5 years, so you can wait if you are early in the loan term.
What if I can only afford an extra payment every other year?
One extra payment every two years saves roughly half the time compared to one per year. The exact amount depends on your rate and loan term, but you would save 2 to 3 years instead of 4 to 7. Any extra principal helps; the more you send, the more time you save.
Does making extra payments hurt my credit score?
No. Extra payments do not hurt your credit. They show that you are paying down debt, which can help your credit over time. Your credit score is based on payment history, credit utilization, and other factors—not on how fast you pay off the loan.
Should I make extra mortgage payments or invest the money instead?
That depends on your interest rate and investment returns. If your mortgage rate is 6 percent and you can reliably earn 8 percent or more in the stock market, investing may build more wealth. If your rate is 7 percent and you are uncertain about investment returns, extra mortgage payments are a may provide return equal to your interest rate. Many people do both: extra payments for peace of mind and investing for growth.
What happens to my monthly payment if I make extra payments?
Your monthly payment stays the same. Extra payments reduce your loan balance and payoff date, but they do not lower your regular monthly payment unless you refinance. You keep paying the same amount each month until the loan is paid off early.