See how extra, lump-sum or bi-weekly payments shorten your mortgage
Updated 2026-09-28
To pay off a mortgage early, pay extra toward principal: every extra dollar lowers the balance, so less interest is charged in every month after it. Enter your balance, rate and remaining term, then add an extra monthly, yearly, lump-sum or bi-weekly payment to see your new payoff date, the months saved and the interest saved. see when PMI ends · compare with a refinance · print the new schedule.
Your loan today
What your plan saves
Interest saved
—
Paid off sooner by
—
New time left
—
Current payment (P&I)
—
Interest left, no extra
$329,276
Current scheduleWith your extra payments
Try other amounts
Extra per month
Paid off in
Interest saved
Estimates for planning, not a loan offer or financial advice. Every rate and cost here is a number you enter or an example you can change; confirm figures with your lender.
How extra payments shorten a mortgage
Interest each month is charged on the balance you still owe. An extra dollar of principal removes that dollar from the balance immediately, so it stops collecting interest for every remaining month of the loan. The regular payment does not change, but more of each later payment goes to principal, and the loan ends early.
Example: a $280,000 balance at 6.75% with 27 years left has a principal-and-interest payment of $1,880 and $329,276 of interest still to pay.
Strategy
Loan ends in
Interest saved
No extra
27 years
—
+$100 a month
23 years 7 months
$49,291
+$200 a month
21 years 1 month
$84,506
+$500 a month
16 years 2 months
$149,403
Bi-weekly
22 years 1 month
$70,544
The four ways to prepay
Extra every month — the steadiest option; even a small amount compounds over decades.
Extra once a year — a bonus or tax refund applied to principal every 12th payment.
Lump sum — a one-time payment, such as an inheritance or the proceeds of selling something. Earlier is better.
Bi-weekly — half the monthly payment every two weeks, which adds one full payment a year. Some servicers charge for bi-weekly programs; you can get the same effect free by adding one-twelfth of your payment each month.
How the calculator works
It builds your current schedule from the balance, rate and years left, then a second schedule with your extras applied to principal in the months you choose, and compares the two. The final payment is only what is owed, so savings are not overstated. Taxes and insurance are left out because they do not change when you prepay. Bi-weekly payments are modeled as one-twelfth of a monthly payment added each month, a close approximation of 26 half-payments a year.
Before you prepay
Keep an emergency fund, and compare your mortgage rate with other uses of the money — especially higher-rate debt and any retirement-plan employer match. The pay off or invest guide covers the trade-off. If you still pay PMI, extra principal also brings forward the month it comes off; the PMI removal calculator shows when. To see every month of the new schedule, open the amortization schedule with an extra amount.
Frequently asked questions
Do bi-weekly payments pay off a mortgage faster?
Yes. Paying half your monthly payment every two weeks makes 26 half-payments a year, which equals 13 full monthly payments instead of 12. That one extra payment a year goes to principal and shortens the loan.
How much does an extra $100 a month save on a mortgage?
It depends on the balance, rate and years left. On a $280,000 balance at 6.75% with 27 years left, an extra $100 a month saves about $49,291 of interest and ends the loan 3 years 5 months early. Enter your own loan to see your figures.
Do bi-weekly payments really pay off a mortgage faster?
Paying half the monthly payment every two weeks makes 26 half payments, or 13 full payments, a year. The extra payment goes to principal, which shortens a 30-year loan by several years. The calculator models it as one-twelfth of a payment added each month; check that your servicer applies bi-weekly payments as they arrive rather than holding them.
Is a lump sum better than extra monthly payments?
Dollar for dollar, money applied to principal earlier saves more interest, so a lump sum today beats the same total spread over later months. Monthly extras are easier to sustain. You can combine both here.
Should I tell my lender the extra is for principal?
Yes. Mark extra amounts as principal-only (most servicers have a box or a separate option online) so they are not held as an early next payment. Check your loan documents for any prepayment penalty; most recent U.S. home loans do not have one.
Should I pay off my mortgage early or invest?
Extra principal earns a guaranteed return equal to your mortgage rate. Investing may earn more or less. Many people first build an emergency fund, capture any employer retirement match and clear higher-rate debt. The pay-off-or-invest guide covers the trade-offs.