Runs in your browser · Last updated 4 September 2026
Free Extra Payment Mortgage Calculator (US)
Free extra payment mortgage calculator. See how extra principal shortens a US fixed-rate loan — interest and months saved in this tab. Nothing is uploaded.
Scheduled P&I
$1,896.20
Payoff
23.1 years
Interest paid
$279,185
Interest saved
$103,449
Months saved
83
Total paid
$579,185
How to use this tool
- Enter balance, note rate, and remaining term.
- Add the extra principal you can send every month.
- Read months saved and interest saved versus paying the scheduled P&I only.
Worked example
$300,000 at 6.5% for 30 years is about $1,896 P&I. An extra $200 a month cuts years of interest — the exact months saved update as you type. Shopping a new purchase? The 28/36 DTI affordability calculator sizes the loan first. If extra principal is aimed at dropping PMI, use the PMI 78/80 calculator. Comparing a new rate instead of extra principal? The refinance break-even calculator clocks closing costs against monthly P&I savings.
Frequently asked questions
- Is extra principal the same as biweekly?
- No. Extra principal is a fixed dollar amount on top of the monthly P&I. Biweekly is half the monthly payment 26 times a year.
- Does this include taxes and insurance?
- No. Only principal and interest. Escrow does not shorten the loan.
- Prepayment penalty?
- Most US closed-end mortgages since 2014 have none. Confirm your note.
- Is the loan uploaded?
- No. The amortization runs in this tab.
- ARM?
- This page is fixed-rate. Recast the remaining balance when the rate resets.