One extra payment a year cuts years off your loan and saves thousands in interest

Making one additional mortgage payment annually—often called a "13th payment" strategy—does shorten your loan term and reduce total interest paid. The math is straightforward: you are paying down principal faster, so less of your remaining balance accrues interest over time. On a 30-year mortgage, one extra payment per year typically cuts 4 to 6 years off the loan and saves between $40,000 and $80,000 in interest, depending on your loan amount, rate, and how early you start.

The catch is that the benefit is real but modest compared to other strategies. A single extra payment per year is not the same as making biweekly payments (26 half-payments, which equals 13 full payments annually) or paying a lump sum toward principal when you have cash on hand. The timing and structure matter more than the round number itself.

Key Takeaways

  • One extra payment per year reduces a 30-year mortgage by roughly 4 to 6 years and saves $40,000 to $80,000 in interest, though the exact figure depends on your loan balance, interest rate, and when you start.
  • The benefit comes from paying principal faster, which means less interest accrues on the remaining balance in future months.
  • Biweekly payment plans deliver the same result as one extra annual payment but spread the extra money across the year, making the cash flow easier to manage.
  • Lump-sum payments toward principal (tax refunds, bonuses, inheritance) often save more interest per dollar than a fixed extra payment, because the timing of when you pay matters.
  • Before committing to extra payments, confirm your mortgage has no prepayment penalty and that extra funds are not being applied to escrow or next month's payment instead of principal.

How one extra payment actually reduces your loan term

When you make a regular monthly payment, part goes to interest (calculated on the current balance) and part goes to principal. Early in the loan, most of your payment is interest. An extra payment goes almost entirely to principal because there is no interest calculation attached to it—you are simply reducing what you owe.

That smaller balance then earns less interest in the following months. Over 30 years, this compounds. If you start making extra payments early (year 1 or 2), the effect is larger because you have more years of reduced interest ahead. If you start in year 20, the savings are smaller but still real.

The exact payoff timeline depends on your loan amount, rate, and payment amount. A $300,000 mortgage at 6.5% will see a different time savings than a $150,000 mortgage at 3.5%. Online mortgage calculators can show you the specific number for your situation—enter your current balance, rate, and remaining term, then run it twice: once with your normal payment and once with an extra payment each year.

Biweekly payments deliver the same result with easier cash flow

Instead of one lump-sum extra payment per year, you can split that amount into 26 biweekly payments (half your normal monthly payment every two weeks). Over a year, this totals 13 full payments—the same as the "one extra payment" strategy—but the money leaves your account gradually rather than in one chunk.

For most households, biweekly payments are easier to manage than saving up for a single large payment. If your paycheck arrives every two weeks, the timing aligns naturally. Some lenders offer biweekly programs directly; others require you to set up the payments yourself through your bank. Be cautious: some third-party biweekly services charge fees ($300 to $500 upfront) that eat into your savings. If your lender offers it directly or your bank can do it for free, use that route instead.

The payoff timeline and interest savings are nearly identical to making one annual extra payment, so choose based on what fits your budget, not on which method is "better."

Lump-sum payments often save more interest than fixed extra payments

If you receive a tax refund, work bonus, inheritance, or other windfall, putting that entire amount toward your mortgage principal saves more interest than spreading it across the year as fixed extra payments. The reason: the sooner you reduce the balance, the sooner interest stops accruing on that money.

A $5,000 lump-sum payment in January saves more interest over the remaining loan term than five $1,000 payments spread across the year. This is especially true early in the loan, when your balance is highest and interest charges are steepest. If you have irregular income or expect occasional large payments, prioritize lump sums over a fixed extra payment schedule.

The trade-off is that lump sums are unpredictable. If you want a may provide way to pay extra every month, the fixed extra payment or biweekly plan is more reliable.

Confirm your lender allows extra payments without penalties or redirects

Before you commit to extra payments, check your mortgage note or call your lender to confirm two things: (1) there is no prepayment penalty for paying off the loan early, and (2) extra payments are applied to principal, not to escrow or next month's regular payment.

Prepayment penalties are rare on mortgages issued after 2010, but some loans still carry them, especially if you refinanced or have an adjustable rate. A penalty can be a flat fee ($500 to $1,000) or a percentage of the prepaid amount (0.5% to 1%). If your loan has one, the interest you save by paying extra may not offset the penalty, so do the math before proceeding.

The second issue is more common: some lenders automatically apply extra payments to your escrow account (which funds property taxes and insurance) or hold the money and credit it to next month's regular payment instead of reducing principal. This defeats the purpose. When you make an extra payment, explicitly instruct your lender in writing (or through their online portal) to apply it to principal only. Confirm in writing that they have done so.

Compare the interest savings to other uses of that money

One extra mortgage payment per year is a solid strategy, but it is not always the best use of available cash. Before committing, consider the alternatives:

  • High-yield savings or money market accounts: If these are paying 4% to 5% and your mortgage rate is 3%, you may earn more by keeping cash liquid than by paying down the mortgage. The difference narrows if your rate is 6% or higher.
  • Retirement contributions: If you are not maxing out a 401(k) or IRA, the tax benefits of retirement savings often outweigh the interest savings from extra mortgage payments.
  • High-interest debt: Credit cards, car loans, or personal loans at 8% or higher should be paid off before extra mortgage payments.
  • Emergency fund: If you do not have 3 to 6 months of expenses in savings, building that buffer is more important than accelerating mortgage payoff.

Extra mortgage payments make sense when you have stable income, an emergency fund in place, no high-interest debt, and cash left over after retirement contributions. If you are juggling multiple financial goals, prioritize in that order before deciding to pay extra on the mortgage.

The real payoff: years saved and interest avoided

The tangible benefit of one extra payment per year is time and money. On a $300,000 mortgage at 6.5% with 30 years remaining, one extra payment per year saves roughly 5 years and $60,000 in interest. On a $150,000 mortgage at 3.5%, the savings are smaller—roughly 3 years and $15,000—but still meaningful.

The earlier you start, the larger the benefit. Starting in year 1 saves more than starting in year 10, because the reduced balance compounds over more years. If you are in your 30s or 40s with a 30-year mortgage, the impact is substantial. If you are in your 50s with 15 years left, the savings are real but smaller.

The psychological benefit is also worth noting: watching your loan balance drop faster than the amortization schedule predicts is motivating, and knowing you will own your home years earlier than planned is valuable in its own right.

Frequently Asked Questions

Will one extra payment per year affect my taxes?

No. Mortgage interest is deductible only if you itemize deductions on your tax return, and paying extra principal does not change that. You will pay less total interest over the life of the loan, which means a smaller deduction in future years, but there is no tax penalty for paying down your mortgage faster.

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

Even one extra payment every two years saves interest and shortens the loan, just not as much as annual extra payments. The benefit scales with frequency: more payments = more savings. Do what your budget allows; something is better than nothing.

Should I make extra payments if I plan to sell the house in 5 years?

Probably not. If you are selling within 5 to 7 years, the interest you save may not offset the transaction costs of selling (realtor fees, closing costs). Use a mortgage calculator to compare the interest saved against your expected sale costs. If the number is close, keep the cash instead.

Can I stop making extra payments if my financial situation changes?

Yes. Extra payments are optional—you are never obligated to make them. If your income drops or an emergency arises, you can pause extra payments and return to your regular monthly payment. Your lender cannot penalize you for paying extra, and you can stop whenever you need to.

Is one extra payment better than paying extra toward principal each month?

The result is the same: both strategies reduce your balance and save interest. The difference is timing and cash flow. One annual payment requires saving $1,000 to $2,000 per month (depending on your payment size) and paying it in a lump sum. Monthly extra principal payments spread the cost across 12 months. Choose based on what is easier for your budget.