One extra payment per year cuts 4 to 8 years off a 30-year mortgage

The exact number depends on your loan balance, interest rate, and when you start making extra payments. A single extra payment applied early in the loan—when most of your payment goes to interest—saves more time than the same payment made near the end. On a $300,000 mortgage at 6.5% interest, one extra payment per year typically removes 4 to 6 years. At 4% interest, the same strategy removes 5 to 7 years. The lower your rate, the longer it takes to see the same payoff benefit, because less of each payment is wasted on interest.

The math works because every extra dollar you send goes straight to principal, skipping the interest calculation entirely. Your lender applies it to the balance owed, which means the next month's interest is calculated on a smaller number. Over time, this compounds: a smaller balance means smaller interest charges, which means more of your regular payment hits principal, which shrinks the balance faster still.

Key Takeaways

  • One extra payment per year typically removes 4 to 8 years from a 30-year mortgage, with the exact number depending on your interest rate and loan balance.
  • Extra payments made early in the loan save more time than the same payments made later, because early payments reduce the principal that accrues interest for decades.
  • You can make one extra payment per year by paying one-twelfth extra with each regular payment, or by sending a lump sum once a year—the timing matters less than consistency.
  • The lower your interest rate, the fewer years you save with the same extra payment, because less of your regular payment is consumed by interest.
  • Your loan documents must allow extra payments without penalty; most mortgages do, but some older loans or certain loan types may charge a prepayment penalty.

How the math changes with different interest rates

Interest rate is the biggest variable. At 3%, one extra payment per year on a $300,000 loan removes roughly 5 to 6 years. At 6%, the same payment removes 6 to 7 years. At 8%, it removes 7 to 8 years. The reason: higher rates mean more of each payment goes to interest instead of principal. When you make an extra payment, you're bypassing that interest entirely, so the benefit is larger in absolute dollars—but the loan is also longer to begin with, so the percentage of time saved stays in a similar range.

A $400,000 mortgage at 5.5% with one extra payment per year removes roughly 5 to 7 years. A $200,000 mortgage at the same rate removes roughly 4 to 6 years. Larger loans take longer to pay off, so the extra payment saves more calendar years on a bigger balance—but the percentage of the original term saved is similar.

When you start matters more than how much you start with

An extra payment in year 1 saves more time than an extra payment in year 15, even though the dollar amount is the same. In year 1, your principal balance is highest, so the interest you avoid by paying it down is spread across decades of future payments. In year 15, the balance is lower, and the interest you avoid is spread across fewer remaining years.

If you can only afford one extra payment per year, start as soon as possible after closing. If you're five years into a 30-year mortgage and just now considering extra payments, you'll still shorten the loan—but you'll save fewer years than if you'd started at year one. This is why refinancing to a shorter term (15 years instead of 30) early in the loan often saves more time than making extra payments on the original 30-year loan.

Three ways to structure one extra payment per year

Monthly extra payment: Divide one full payment by 12 and add that amount to your regular payment each month. If your payment is $1,800, you'd pay $1,950 each month. This spreads the benefit evenly and is easiest to automate. Most lenders accept this without question.

Quarterly extra payment: Send one-quarter of a full payment every three months, in addition to your regular payment. This is useful if your income arrives in chunks (bonus, commission, seasonal work). The benefit is slightly smaller than monthly because the money sits in your account longer before reaching the lender, but the difference is minimal.

Annual lump sum: Send one full extra payment once per year, usually in a month when you have cash on hand (tax refund, year-end bonus). This is the simplest to track and requires the least discipline, but the benefit is smallest because the money doesn't reach the lender until late in the year. The interest you avoid is only for the remaining months of that year, not the full 12 months.

Check your loan documents for prepayment penalties

Most mortgages allow unlimited extra payments without penalty. However, some loans—particularly older mortgages, certain FHA loans, or loans sold to specific investors—may include a prepayment penalty that charges you a fee if you pay off the loan early or pay it down too quickly. The penalty is usually a percentage of the amount prepaid or a flat fee, and it can range from a few hundred dollars to several thousand.

Your loan documents should state whether a prepayment penalty applies. Look for language about "prepayment", "early payoff", or "acceleration". If you're unsure, call your lender's customer service line and ask directly: "Does my loan have a prepayment penalty?" If it does, calculate whether the years saved are worth the fee. On a 30-year mortgage, one extra payment per year saves enough interest that the fee is usually worth paying—but run the numbers with your lender's payoff calculator first.

How extra payments interact with your interest deduction

If you itemize deductions on your tax return, extra mortgage payments reduce the interest you can deduct in future years. This is not a reason to avoid extra payments—the interest savings over the life of the loan far exceed the tax deduction—but it's worth understanding. In year 1, you might deduct $18,000 in mortgage interest. If you make extra payments, that deduction shrinks to $17,500 in year 2, then $17,000 in year 3, and so on. Over time, your tax deduction becomes smaller, which means your tax refund may be smaller.

The trade-off is straightforward: you pay less interest overall (saving thousands of dollars), but you lose some of the tax benefit of that interest. For most borrowers, this is a worthwhile trade. If you're in a high tax bracket and rely heavily on the mortgage interest deduction, consult a tax professional before committing to a large extra-payment strategy.

What happens if you stop making extra payments

You can start and stop extra payments whenever your cash flow allows. If you make extra payments for three years, then stop, you've still shortened the loan by roughly one to two years—the benefit doesn't disappear. Your regular payment schedule resumes as if nothing changed; the lender doesn't penalize you or adjust your payment upward.

Some borrowers use extra payments strategically: they make them during high-income years (when a bonus is large or business is good) and skip them during lean years. This flexibility is one advantage of extra payments over refinancing to a shorter term, which locks you into a higher monthly payment whether your income is stable or not.

Frequently Asked Questions

Will making one extra payment per year let me pay off my mortgage in half the time?

No. One extra payment per year removes 4 to 8 years from a 30-year mortgage, not 15 years. To cut the term in half, you'd need to make roughly 12 to 15 extra payments per year (one extra payment per month or more), which requires significantly more cash. Refinancing to a 15-year mortgage is a faster way to cut the term in half, but it raises your monthly payment.

Does it matter which month I make my extra payment?

No. The lender applies extra payments to principal immediately, regardless of when in the year you send it. Making it in January versus December saves roughly the same amount of time. Choose the month that fits your cash flow best—after a bonus, tax refund, or other predictable income.

Can I make extra payments if I'm behind on my mortgage?

No. If you're behind on payments, the lender will apply any extra money you send to the overdue balance first, not to principal paydown. Get current on your regular payments before attempting extra payments. If you're struggling to keep up, contact your lender about a loan modification or forbearance before falling further behind.

What if I refinance after making extra payments—do I lose the benefit?

No. The principal you've paid down stays paid down. If you've reduced your balance from $300,000 to $280,000 through extra payments, you refinance the $280,000 balance, not the original amount. You keep the time and interest you've already saved.

Is one extra payment per year better than investing the money instead?

That depends on investment returns and your interest rate. If your mortgage is 6% and you can reliably earn 8% or more in the stock market, investing may build more wealth. If your mortgage is 7% and stock returns are uncertain, paying down the mortgage is safer. Most financial advisors suggest doing both: make one extra payment per year, then invest any remaining surplus. This balances debt reduction with wealth building.