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Prepayment Calculator

See how extra payments shorten the loan and cut total interest. Mix three strategies — a one-time lump sum, recurring extra monthly principal, and biweekly payments — to compare the payoff against your original schedule.

Your loan

$
%

Illustrative example rate.

yrs

Optional. Leave at 1 if starting fresh.

Prepayment strategies

$

Added to every monthly payment.

$

Which payment # does the lump sum land on?

Prepayment summary

These prepayments pay the loan off 5 years, 4 months earlier and save about $113,223 in interest.

Headline outcomes

Interest saved$113,223
Months saved64 (5y 4m)
New payoff dateFebruary 1, 2051
Original payoff dateJune 1, 2056

Side-by-side

Original total interest$535,687
With prepayment interest$422,464
Original months360
With prepayment months296
Results are estimates based on user inputs and do not represent loan terms, APR, or a financing offer. Pre-filled values are illustrative examples, not available or quoted rates. Actual terms depend on credit, property, program, and underwriting.

Original schedule vs with prepayment

Principal vs interest by year
Loan balance over time
YearPaymentsInterestPrincipalExtraBalance
Year 1 (2026)$17,128$13,603$2,326$1,200$416,474
Year 2 (2027)$34,256$26,853$5,003$2,400$409,071
Year 3 (2028)$34,256$26,357$5,499$2,400$401,172
Year 4 (2029)$34,256$25,828$6,028$2,400$392,744
Year 5 (2030)$34,256$25,264$6,593$2,400$383,751
Year 6 (2031)$34,256$24,661$7,195$2,400$374,156
Year 7 (2032)$34,256$24,019$7,838$2,400$363,919
Year 8 (2033)$34,256$23,333$8,523$2,400$352,995
Year 9 (2034)$34,256$22,602$9,255$2,400$341,341
Year 10 (2035)$34,256$21,821$10,035$2,400$328,906
Year 11 (2036)$34,256$20,988$10,868$2,400$315,638
Year 12 (2037)$34,256$20,100$11,757$2,400$301,481
Year 13 (2038)$34,256$19,152$12,705$2,400$286,376
Year 14 (2039)$34,256$18,140$13,716$2,400$270,260
Year 15 (2040)$34,256$17,061$14,796$2,400$253,064
Year 16 (2041)$34,256$15,909$15,947$2,400$234,717
Year 17 (2042)$34,256$14,680$17,176$2,400$215,141
Year 18 (2043)$34,256$13,369$18,487$2,400$194,254
Year 19 (2044)$34,256$11,970$19,886$2,400$171,968
Year 20 (2045)$34,256$10,478$21,378$2,400$148,190
Year 21 (2046)$34,256$8,885$22,971$2,400$122,819
Year 22 (2047)$34,256$7,186$24,670$2,400$95,749
Year 23 (2048)$34,256$5,373$26,483$2,400$66,866
Year 24 (2049)$34,256$3,439$28,417$2,400$36,049
Year 25 (2050)$34,256$1,375$30,481$2,400$3,168
Year 26 (2051)$3,187$19$2,968$200$0

Want to stress-test a prepayment plan?

Talk it through with a loan officer. We'll walk through whether extra principal, a recast, or a refinance gets you to your goal faster.

Discuss Your Scenario

Frequently asked questions

How does a biweekly mortgage actually work?
You pay half a monthly payment every two weeks. There are 26 two-week periods in a year, so you end up making the equivalent of 13 monthly payments per year instead of 12. That extra payment goes to principal.
Is a lump sum or a recurring extra payment better?
Either works. A lump sum saves the most interest per dollar when applied early in the loan. Recurring extras are easier to budget. Mixing both lets you attack the balance from two angles.
Will my lender let me make extra principal payments?
On a standard U.S. mortgage, yes, with no prepayment penalty. Mark the extra as a principal-only payment so it applies to the balance, not toward next month's scheduled payment.
Should I prepay the mortgage or invest the money?
Depends on the rate. If your mortgage rate is higher than what you'd safely earn after tax, prepaying wins. If it's materially lower, investing usually wins on a long horizon. This calculator shows the interest savings side only — you decide the trade-off.

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Related reading

Want the story behind the numbers?

  • ArticleHow much house can you actually afford?Make sure extra payments fit your overall budget.Read
  • HubWhen to refinanceCompare prepay against a full refi at today's rates.Read
  • ArticleWhat actually moves mortgage rates (and what does not)Why prepaying is sometimes better than waiting on rates.Read

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