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How Extra Payments Save Interest

The fastest way to save on a mortgage is not a refinance — it is paying a little extra toward principal. Because interest is calculated on the remaining balance, every extra dollar compounds into real savings.

The math

On a $400,000 loan at 6.5% for 30 years, an extra $100 a month saves about $70,000 in interest and cuts the term by roughly 4 years. An extra $300 saves far more.

Why it compounds

Every extra dollar reduces the balance, which reduces next month's interest, which means more of your regular payment goes to principal. It is a positive feedback loop.

Do not prepay — apply to principal

Always specify that the extra amount goes to principal, not future payments. Prepaying interest earns you nothing.

When to skip it

If you have higher-interest debt (credit cards), pay that first. A 6.5% mortgage is cheap compared to 20% credit-card interest.

Use the extra payment field on our calculator and watch the interest-saved number move in real time.

See your real payment

Reading is step one. Step two is running your own numbers — taxes, insurance, PMI and all.

Open the mortgage calculator