Mortgage Payoff Strategy Comparison

There is more than one way to pay a mortgage down early, and the ones people argue about are closer together than the argument suggests. This page starts from where your loan actually is, the balance and the years left, and runs four routes side by side so you can see the gap rather than guess at it.

The four it compares

• Extra every month. The one everybody means by “overpaying”. Steady, and the compounding works from the first month.
• The same money once a year. Twelve months of that extra, paid as a single lump. Easier if your spare cash arrives as a bonus or a tax refund rather than in monthly dribs.
• Rounding the payment up. If the payment is $1,847, you pay $1,900. Painless, and it needs no decision each month.
• One lump sum today. A windfall thrown at the balance now, with the payment left alone afterwards.

Why the monthly version wins, and by how little

Paying monthly beats the annual lump of the same total, because each instalment stops accruing interest as soon as it lands rather than waiting up to eleven months. On a typical loan the gap is real but small, usually a few thousand dollars over the life of the mortgage and a month or two on the payoff date. If the annual version is the one you will actually keep doing, take the annual version. A strategy you abandon in March saves nothing.

Not proportional, and this is the part that surprises people

Doubling the extra payment does not double the saving. On a $300,000 loan at 7% over 30 years, $100 a month saves $69,338 and $200 saves $116,640, not $138,676. Each further dollar buys slightly less, because the loan is already shortening under the dollars before it.

How mortgage amortization works

Each monthly payment splits between interest and principal:

Monthly interest = Remaining balance × Monthly interest rate

The rest reduces the principal. As the principal falls, the interest share of each payment falls with it and more goes to principal. That is why extra payments early in a loan matter so much more than late ones: they remove principal that all the future interest would have been charged on.

Worked figures on a $300,000 30-year mortgage at 7%

Standard payment $1,995.91, and left alone it costs $418,527 in interest.

Ignore interest entirely and count the cash, which is the version that convinces people. Left alone you hand the bank $718,527 over 360 payments. Paying $2,195.91 you are done in 275 months and hand over $601,887, the last of those payments being a part one. You keep the difference and you stop paying seven years sooner.

Just want the one strategy? If you only care about extra monthly payments on a loan from its start, the extra mortgage payment savings calculator does that in three fields.

Important: Always tell the lender that extra money goes to principal reduction, not toward next month’s payment. Some servicers park it as a prepaid instalment by default, which saves you nothing at all.