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Your monthly payment, the full amortization schedule — and exactly what extra payments save you in interest and years.
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Remaining balance over time
Why extra payments are so powerful
Here's the thing most people miss about mortgages: in the early years, your payment is mostly interest. On a $400,000 loan at 6.5%, your first $2,528 payment breaks down as $2,167 interest and just $362 principal. The bank gets paid first; you build equity slowly.
Extra payments flip this dynamic because every extra dollar goes straight to principal. That immediately shrinks the balance that next month's interest is calculated on — and the month after that, and the month after that. It's compounding working for you instead of against you.
The numbers are startling: that same $400,000 loan costs $510,178 in total interest over 30 years. Add just $200 a month and you save roughly $112,000 in interest and own your home 5 years and 7 months earlier. That's a 7.9% larger payment buying a 22% shorter loan.
Two practical notes: first, confirm your lender applies extras to principal (most do, but ask — and check for prepayment penalties, which are rare on modern US mortgages). Second, extra payments are a use of money with an opportunity cost — if your rate is 3% and you'd rather invest, our mortgage vs invest calculator compares both paths with your numbers.
Educational content only — not financial advice. Principal & interest only; taxes, insurance, and HOA aren't included.