Does One Extra Mortgage Payment a Year Really Matter?

Yes, and more than most people expect. On a $280,000 30-year loan at 6.76 percent, adding one-twelfth of the payment to every month (the same thing as one extra payment a year) pays the loan off six years early and saves about $88,600 in interest. You do not need a biweekly program or a fee to do it.

The reason a small extra amount does so much is the shape of amortization. Early on, most of every payment is interest, so every extra dollar of principal you retire now stops charging interest for the next two or three decades. Below is the math on a loan that looks like a typical York County purchase today, and the three ways people go about it.

Why does most of my early payment go to interest?

Because interest is charged on the balance, and the balance is biggest at the start. Take $280,000 at 6.76 percent, the Freddie Mac average 30-year rate for the week of September 10, 2026. The payment is $1,817.94. In month one, $1,577.33 of that is interest and only $240.60 is principal. The crossover point, where the principal share of the payment finally exceeds the interest share, does not arrive until payment 238, almost 20 years in. Over the full 30 years that loan pays $374,457 in interest, more than the amount borrowed.

What does $100 a month extra actually do?

It knocks four years off the loan. Same $280,000 at 6.76 percent, extra amount sent every month from the first payment:

Extra each month	Paid off in	Years saved	Total interest	Interest saved
$0	30.0 years	0	$374,457	$0
$100	25.7 years	4.3	$310,073	$64,384
$151.49 (one-twelfth of the payment)	24.0 years	6.0	$285,847	$88,610
$200	22.6 years	7.4	$266,623	$107,834

Notice the extra dollars are not earning a return; they are avoiding a cost, and the cost they avoid is your own 6.76 percent rate, guaranteed and tax-free. The habit matters more than the amount. $25 a month, a tax refund, a bonus: anything sent to principal in the early years does outsized work.

Are biweekly payment programs worth paying for?

No. The trick is real; paying for it is the gimmick. A year has 26 two-week periods, so paying half your mortgage payment every two weeks makes 26 half-payments, which is 13 full payments instead of 12. That is the $151.49 row above. Third-party programs charge you to hold your half-payments and forward them, and some just send the normal payment monthly and pass the extra along once a year. You can get the identical result free by dividing your payment by 12 and adding that amount to every monthly payment, marked "apply to principal." You can also stop whenever life gets tight, which a program contract may not let you do.

How do I make sure the extra goes to principal?

Use the separate "additional principal" field on your servicer's payment screen, then check the next statement to confirm the balance dropped by the extra amount. If you just overpay without marking it, some servicers treat it as an early payment of next month. On prepayment penalties: the standard Fannie Mae and Freddie Mac fixed-rate note (Form 3200) says you "may make a full Prepayment or partial Prepayments without paying a Prepayment charge," and Pennsylvania's Act 6 regulations (10 Pa. Code 7.8) let residential mortgage obligations contracted since January 30, 1974 be prepaid without penalty. If your loan is not a standard conforming note, read the prepayment section of your own note before you start.

How do I read my amortization schedule?

Log in to your servicer's site and search "amortization"; it lists every payment for the life of the loan split into principal and interest. Write down three numbers: your current split, your crossover payment number, and total interest over the life of the loan. Then find today's row and look at the principal column a year ahead. Every extra dollar you send now crosses those future rows off early, and the interest attached to them is never charged. It turns "pay extra when you can" into a number you can watch move.

Send me your balance, rate and remaining term and I will send back a payoff comparison with the crossover marked. It takes me five minutes. Call or text me at 717-356-9413. This is general information, not legal or tax advice.