Extra Mortgage Payment Calculator
Add a fixed extra principal amount each month and see how much sooner you could pay off the loan — and how much interest you might avoid.
Why extra principal shortens the loan
A standard payment covers accrued interest first; what’s left reduces principal. Send more to principal and the balance drops faster, so later months charge interest on a smaller amount.
Small extras, paid every month, add up — especially early, when interest takes a large share of each payment. Use the Amortization Calculator to see how those payments change the remaining-balance schedule.
Worked example
On a $300,000 loan at 6.75% for 30 years, scheduled P&I is about $1,945.79. An extra $100 per month pays the loan off in about 311 months instead of 360 — saving roughly 4 years and about $65,000 in interest. Your numbers will differ based on rate, term, and extra amount.
How extra payments reduce interest · Should you make extra payments?
Assumptions
- Extra amounts apply to principal starting the month entered.
- Fixed rate; no prepayment penalties modeled.
- Does not include taxes, insurance, PMI, or HOA.