Mortgage Extra Payment Calculator
Last updated: October 15, 2026
See how an extra monthly mortgage payment can reduce interest and payoff time.
Time saved
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- New payoff time: —
- Interest saved: —
- Scheduled payment: —
On this page
Quick summary: See how an extra monthly mortgage payment can reduce interest and payoff time.
Read the method, example and limitations
Updated reference sections in this guide are in English.
Guide language: English. Updated October 15, 2026.
What this calculator estimates
Mortgage Extra Payment Calculator
Inputs and units
Use the units shown for Original loan amount ($), Interest rate (%), Loan term, Extra monthly payment ($). Required fields cannot be blank. Use zero only where that field and the model allow it. Select Calculate after changing a scenario.
Method and assumptions
Calculate the scheduled monthly payment, then compare two monthly schedules: the scheduled payment alone and that payment plus the extra. Interest accrues before each payment. The final payment is capped at the balance due. Time saved is the difference between completed schedules; interest saved is their interest difference.
Worked example
At 0%, a 12,000 balance over 24 months has a 500 scheduled payment. Adding 500 repays it in 12 months, saving one year and no interest.
Limitations
Use 1 to 1,200 whole months. Taxes, insurance, prepayment penalties and changes in rate are excluded. An unfinished schedule is not a payoff date.