Mortgage Payoff Calculator
See how much sooner you finish and how much interest you save by paying extra each month or in lump sums.
Your details
Extra payments
Twenty-six half payments a year equals thirteen monthly payments, so it acts like one extra payment annually.
This calculator runs entirely on your device. Nothing you enter is uploaded, stored, or sold. How this works
Interest saved
$110,045
paid off 7y 2m sooner
Includes your inputs, the full breakdown, and every row of the table.
New payoff time
19y 10m
Original payoff time
27y 0m
Required payment
$2,097.78
Total you actually pay monthly
$2,397.78
- Balance today
- $320,000
- Scheduled payment
- $2,097.78
- Extra per month
- $300.00
- Interest without extra payments
- $359,679
- Interest with extra payments
- $249,634
- Interest saved
- $110,045
- Total extra paid in
- $71,400
| Year | Principal | Interest | Balance |
|---|---|---|---|
| Year 1 | $8,215 | $20,558 | $311,785 |
| Year 2 | $8,765 | $20,008 | $303,019 |
| Year 3 | $9,352 | $19,421 | $293,667 |
| Year 4 | $9,979 | $18,795 | $283,688 |
| Year 5 | $10,647 | $18,126 | $273,041 |
| Year 6 | $11,360 | $17,413 | $261,681 |
| Year 7 | $12,121 | $16,652 | $249,560 |
| Year 8 | $12,933 | $15,841 | $236,628 |
What this means
- Every dollar of extra payment returns 154 cents in avoided interest here — a guaranteed, tax-free return equal to your 6.50% mortgage rate.
- Extra payments only work if your servicer applies them to principal. Many default to holding them as a prepayment of next month's bill, which achieves nothing — check the option or memo line every time.
- Paying down a 6.50% mortgage is equivalent to a guaranteed 6.50% return. Compare that against what the same money would do in the market after tax, and against the value of keeping it liquid.
How the mortgage payoff calculation works
Mortgage interest is front-loaded, which is why extra payments so early in a loan have such a disproportionate effect. In the first years almost all of your scheduled payment services interest, so an extra hundred dollars towards principal removes not just that hundred from the balance but every future interest charge that would have accrued on it for the remaining decades. The same hundred dollars paid in year twenty-five saves almost nothing.
The biweekly trick works through arithmetic rather than magic. Paying half your monthly amount every two weeks produces twenty-six half payments a year, which is thirteen monthly payments rather than twelve. That thirteenth payment is the entire benefit, and you can capture it just as effectively by dividing one payment by twelve and adding it to each month — without paying a servicer a setup fee for the privilege.
Whether to do any of this is a genuine question rather than an obvious yes. Paying down a mortgage is a guaranteed after-tax return equal to your interest rate, with no volatility. Against a six or seven percent mortgage that is a strong risk-free return and hard to argue with. Against a three percent mortgage it is much weaker than the long-run return on index funds. The other side of the ledger is liquidity: money paid into a mortgage is very hard to get back out, and a fully funded emergency reserve should come first.
Frequently asked questions
Is it better to pay off my mortgage early or invest the money?
It depends on your rate. Paying down a mortgage is a guaranteed return equal to the interest rate, so against six or seven percent it is competitive with equities on a risk-adjusted basis. Against a rate below four percent, investing has historically won by a wide margin. Emergency savings and any employer retirement match should come before either.
Do biweekly payments really save money?
Yes, but only because twenty-six half payments equal thirteen monthly payments rather than twelve. You get the identical result by adding one-twelfth of your payment to each month, and you avoid the fees some servicers charge to set biweekly billing up.
Will my monthly payment go down if I pay extra?
No. Extra payments shorten the term rather than reducing the payment, so you finish earlier while still owing the same amount each month. Lowering the payment requires a formal recast, which some lenders offer for a fee after a large lump sum.
Are there penalties for paying off a mortgage early?
Rarely on modern owner-occupied loans in the US, where prepayment penalties are heavily restricted on qualified mortgages. They still appear on some investment property, non-qualified and older loans, so it is worth checking your note before making a large lump payment.
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Disclaimer. This calculator is provided for general information and educational purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Results are estimates based on the inputs you provide and the assumptions described above. Confirm any figure with a qualified professional before acting on it.