Estimate how much faster you can pay off the mortgage.
Start from the current balance and payment, then see how extra monthly payments change the payoff timeline and lifetime interest.
See how fast extra payments eat into the loan
This page starts from an existing balance and payment rather than a purchase price. It is for the phase where someone already has a mortgage and wants to know whether throwing extra cash at it is actually worth it.
- How many months early you could kill the mortgage.
- Whether a modest recurring extra payment materially changes lifetime interest.
- How quickly the remaining balance starts to bend downward.
Use this when you already have a loan balance and payment and want to test a fixed extra amount each month.
The most useful outputs are usually months saved and interest saved. If the payment is too low to reduce principal, the calculator now flags that state instead of showing a fake payoff path.
Compare your current payment against the same payment plus an extra fixed amount. A smaller recurring extra payment often matters more than people expect because it reduces principal early.
Results are informational estimates only. Servicer rules, adjustable rates, fee changes, and inconsistent extra payments can change the real payoff path.
Maintained by David K. ยท Last reviewed: July 23, 2026