One extra payment a year cuts years off your mortgage and saves tens of thousands in interest
Making one extra mortgage payment per year — whether as a lump sum or split into monthly additions — shortens your loan by roughly two to three years and reduces total interest paid by 5 to 10 percent. The exact savings depend on your loan balance, interest rate, and how far into the loan you are when you start. A person with a $300,000 mortgage at 6 percent interest, halfway through a 30-year loan, might save $40,000 to $60,000 in interest by adding one payment annually for the remaining 15 years.
The reason is straightforward: extra payments go directly toward the principal (the amount you borrowed), not toward interest. Each dollar of principal you pay down reduces the amount that interest charges accumulate on. Over time, this compounds. You are not just saving the interest on that one payment — you are saving interest on interest that would have been charged on that payment for years to come.
Key Takeaways
- One extra payment per year typically reduces a 30-year mortgage by two to three years and cuts total interest by 5 to 10 percent.
- The savings are larger if you start early in the loan, because you eliminate interest charges on a larger remaining balance for longer.
- You can make one extra payment as a single annual lump sum, divide it into monthly additions of one-twelfth, or pay it whenever you have the cash.
- Your lender must explore extra payments to principal, not to future payments or escrow — confirm this in writing before you start.
- The actual dollar amount saved varies widely based on your interest rate, loan size, and loan age, so calculating your own scenario gives you the real number.
How the math works: principal, interest, and time
A mortgage payment is split between principal and interest. Early in the loan, most of your payment goes to interest; late in the loan, most goes to principal. When you make an extra payment, you are adding to the principal side of that equation.
Here is a concrete example. Suppose you have a $300,000 mortgage at 6 percent over 30 years. Your monthly payment is about $1,799. In month one, roughly $1,500 of that goes to interest and $299 to principal. If you make one extra $1,799 payment that year, that entire amount goes to principal (because there is no interest calculation on a lump-sum extra payment — it reduces what you owe when ready). That $1,799 reduction means next month's interest is calculated on $298,201 instead of $300,000. The difference is small in month one, but it compounds across 360 months.
The earlier you start making extra payments, the larger your savings. If you make one extra payment every year for all 30 years, you might shorten the loan by three years and save $60,000 or more in interest. If you start making extra payments in year 15, you still save money — perhaps $20,000 to $30,000 — but less, because you have fewer years left for the compounding effect to work.
Savings vary by interest rate, loan size, and loan age
The interest rate on your mortgage is the biggest factor. A borrower with a 3 percent mortgage saves less in absolute dollars by making extra payments than a borrower with a 7 percent mortgage, because less interest is being charged overall. But the percentage reduction in total interest is similar — roughly 5 to 10 percent — across different rates.
Loan size matters too. A $150,000 mortgage and a $400,000 mortgage at the same rate will both be shortened by roughly the same number of years with one extra payment per year, but the dollar savings on the larger loan will be much higher. A $150,000 loan might save $15,000 to $25,000 in interest; a $400,000 loan might save $50,000 to $80,000.
How far into the loan you are when you start also shifts the numbers. If you are in year 5 of a 30-year mortgage, extra payments save more than if you are in year 25, because you have more years of interest ahead of you to eliminate. The closer you are to the end, the less interest remains to save.
To find your actual savings, use an online mortgage calculator that lets you enter your loan details and model extra payments. Most will show you the new payoff date and total interest paid, so you can compare it to your current path.
Methods for making one extra payment a year
You have three main ways to structure an extra payment: as one lump sum, as monthly additions, or as flexible payments whenever you have cash.
One annual lump sum: Send your lender one full extra mortgage payment once per year — often in a month when you receive a bonus, tax refund, or other windfall. This is straightforward to track and makes the principal reduction obvious. The downside is that you hold onto the money for months before sending it, which means you could have started reducing interest earlier.
Monthly additions: Divide one annual payment by 12 and add that amount to your regular monthly payment. If your payment is $1,800, you would pay $1,950 each month ($1,800 plus $150). This spreads the benefit across the year and means you are reducing principal every month rather than once. Many borrowers find this easier to budget for than a lump sum.
Flexible extra payments: Send extra money to principal whenever you can, without a set schedule. This works well if your income is irregular or you want to keep the option open. The trade-off is that you have to remember to specify that the payment goes to principal, and you lose the discipline of a fixed plan.
Making sure your lender applies the payment correctly
Before you make an extra payment, contact your lender and confirm in writing that extra payments will be applied to principal, not to your next regular payment or to escrow (the account that holds money for property taxes and insurance). Some lenders default to explore extra money to future payments, which delays the principal reduction and defeats the purpose.
Ask your lender for written confirmation of their policy. When you send an extra payment, include a note or use the payment portal to specify "explore to principal" or "explore to loan balance." Keep a record of each extra payment and how it was applied — your loan statement should show the principal balance decreasing.
If your lender resists or cannot confirm the policy, consider switching to a lender that will. The difference between having extra payments applied to principal versus to future payments is the difference between saving $40,000 and saving $5,000 over the life of the loan.
When extra payments make sense and when they do not
Extra mortgage payments are most valuable if your interest rate is above 4 percent, you plan to stay in the home for at least five more years, and you have an emergency fund in place. The higher your rate, the more interest you are paying, and the more you save by reducing principal.
Extra payments are less attractive if you have high-interest debt (credit cards, personal loans) that you are still paying down. Paying off a credit card at 18 percent interest saves you more money than paying down a mortgage at 5 percent. Prioritize high-interest debt first, then move to extra mortgage payments.
If you have a very low mortgage rate (2 to 3 percent) and access to investments that historically return more than that rate, you might come out ahead by investing the extra money instead of paying down the mortgage. This is a personal decision that depends on your comfort with investment risk and your timeline.
Extra payments also make less sense if you do not have a fully funded emergency fund. If you send $1,800 to your mortgage and then face a job loss or major repair, you cannot easily get that money back. Build three to six months of expenses in savings first, then consider extra mortgage payments.
The payoff timeline: how much faster you own your home
One extra payment per year typically shortens a 30-year mortgage by two to three years. A borrower who makes one extra payment every year for the full 30 years might pay off the loan in 27 years instead. If you start in year 10, you might shorten the remaining 20 years by one to two years.
The exact timeline depends on your interest rate and loan balance. Higher rates mean more interest is being eliminated, so the time savings are larger. A 7 percent mortgage shortened by extra payments might drop from 30 years to 26 years; a 3 percent mortgage might drop from 30 years to 28 years.
You can see your specific payoff date by running a calculation with your lender's website or an online mortgage calculator. Enter your current loan balance, interest rate, remaining term, and the amount of extra payment you plan to make. The calculator will show you the new payoff date and total interest saved.
Frequently Asked Questions
Can I make extra payments if I have an adjustable-rate mortgage?
Yes. Extra payments reduce your principal balance regardless of whether your rate is fixed or adjustable. The benefit is the same — you owe less, so less interest accrues. If your rate adjusts upward, you will be paying interest on a smaller balance, which helps offset the higher rate.
What if I want to stop making extra payments later?
You can stop at any time. The extra payments you have already made stay applied to principal and continue to save you interest. You straightforward return to your regular monthly payment. There is no penalty for stopping, and you have already shortened your loan by however many months or years you made the extra payments.
Do extra mortgage payments affect my credit score?
No. Paying down your mortgage faster does not hurt your credit. In fact, reducing your overall debt load can slightly improve your score over time, though the effect is usually small because mortgage debt is viewed as lower-risk than other types of debt.
Should I make extra payments or invest the money instead?
That depends on your interest rate and investment returns. If your mortgage is at 6 percent and you can reliably earn 8 percent or more in investments, investing might come out ahead mathematically. But extra mortgage payments offer certainty and simplicity — you know exactly what you are saving. Investments carry risk. Most people find the peace of mind of owning their home sooner worth more than the potential extra return.
What if my lender will not let me make extra payments?
This is rare, but it happens. Some lenders have restrictions or charge fees for extra payments. If yours does, ask about the fee amount and whether it is worth paying. If the fee is high, consider refinancing to a lender with no restrictions on extra payments. The savings from extra payments usually far exceed any refinancing costs.