How to use this calculator
- Choose Original loan if you know the amount you borrowed, the rate, the term and your first payment date. Your Closing Disclosure lists them.
- Choose Current balance if you only have a recent statement. Enter the principal balance, the rate and your monthly principal-and-interest payment (or the number of payments left). Results are then measured from your next payment.
- Add up to five plans. Each plan can combine an amount every month, a yearly lump sum, one-time payments, a set period, or an amount that rises each year.
- Fine-tune any month by editing its Extra amount in the payment schedule. You can apply a change to that month only or to every later month.
- Copy the share link to send your exact setup to someone, or print or save the report as a PDF.
Reading your results
- Interest saved is your current schedule's total interest minus the plan's total interest.
- Paid off is the month the plan's balance reaches $0, and time saved is how much sooner that is than your current schedule.
- Extra principal is the sum of every extra amount in the plan.
- In the schedule, principal and interest are the two parts of your regular payment; extra is paid on top and goes entirely to principal.
Why early extra payments matter most
Each month's interest is charged on the balance you still owe. Early in a mortgage the balance is at its highest, so most of each payment goes to interest. An extra dollar paid early lowers the balance for every month that follows, which is why the same extra amount saves more when it starts sooner. The chart shows this as the gap between each plan's line and your current schedule.
Common questions
Does an extra payment lower my monthly payment?
On most fixed-rate mortgages, no. The required payment stays the same and the loan ends sooner, which is how this calculator models extra payments. Some lenders offer a recast, which lowers the payment after a large lump sum, usually for a fee.
How do I make sure extra money goes to principal?
Ask your loan servicer how to send it. Many servicers let you mark a payment as principal-only online or on the payment coupon. Check your next statement to confirm it was applied to principal.
Is one extra payment a year better than a little each month?
For the same yearly total, spreading it across the months usually saves a bit more interest, because each dollar starts lowering the balance sooner. Add both as plans to see the difference for your loan.
What does paying biweekly do?
Paying half your monthly payment every two weeks adds up to 26 half-payments, or 13 full payments a year instead of 12. Some servicers hold half-payments until a full payment arrives, and some biweekly programs charge fees, so ask how yours handles it.
Are taxes, insurance and PMI included?
No. The calculator covers principal and interest only. Escrow amounts for property taxes and insurance are separate from the principal and interest part of your payment.
Is there a penalty for paying off a mortgage early?
Some loans have a prepayment penalty. Your Loan Estimate and Closing Disclosure state whether your loan has one; you can also ask your servicer before making large extra payments.
Why might my lender's numbers differ?
Lenders may calculate interest daily, apply payments on specific dates and round differently. This calculator estimates interest monthly, so treat its figures as close estimates rather than payoff quotes.