Complete guide
Mortgage payoff calculator with extra payments
Enter the current balance, rate and remaining term, then add optional monthly, annual or immediate principal. Calculator24 compares payoff dates, total interest, savings and the accelerated schedule.
Build the current baseline
Use today's principal balance and remaining term, not the original loan amount and original term. The baseline payment is recalculated as a fixed principal-and-interest payment.
How extra principal works
A lump sum lowers the starting balance; monthly extra accompanies every payment; annual extra is added every twelfth payment. Interest then accrues on the smaller balance.
monthly interest = balance × annual rate ÷ 12 ÷ 100Interest and time saved
The engine runs baseline and accelerated schedules separately. Savings are baseline interest minus accelerated interest; months saved compare their payoff lengths.
Apply payments correctly
Tell the servicer to apply extra money to principal and verify the next statement. The calculator cannot see suspense accounts or servicer processing rules.
Penalties and excluded costs
CFPB notes that some mortgages can charge a prepayment penalty under stated conditions. Review the note and disclosure. Escrow, taxes, insurance and opportunity cost are excluded.
Extra-payment options
| Option | Timing | Effect |
|---|---|---|
| Lump sum | Now | Lowers starting balance |
| Monthly extra | Every payment | Steady acceleration |
| Annual extra | Every 12th payment | Periodic reduction |
Frequently asked questions
Do extra payments reduce mortgage interest?
Yes when applied to principal, because later interest is calculated on a smaller balance.
Should I enter the original balance?
Use the current unpaid principal balance.
Can I combine extra-payment types?
Yes. The schedule applies all three entered options.
Does this include escrow?
No. It models principal and interest only.
Could a prepayment penalty apply?
Possibly. Check the note and servicer disclosure before paying extra.
What to keep in mind
Confirm servicer instructions and whether a prepayment penalty applies. Escrow, fees and changing rates are excluded.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.