Mortgage Prepayment Calculator
Using the approach of making an immediate early repayment after the repayment for installment N is posted, compare reducing the monthly payment with shortening the term, and list the interest, penalty, and estimated net savings separately.
How to use the mortgage prepayment calculator
The loan amount, interest rate, repayment progress, and settlement costs are calculated only in the current browser and are not uploaded or saved.
Enter the original loan
Enter the principal, annual interest rate, original term, and equal principal-and-interest or equal-principal repayment method, and fill in the number of installments that have been successfully credited.
Set up early repayment
Enter the principal to repay early, then choose either lower monthly payments with the term unchanged or a shorter term with approximately unchanged monthly payments; supplement the current-period interest and penalty according to the institution’s settlement statement.
Compare and export
Review the remaining principal, new term or new initial monthly payment, gross interest savings, settlement costs, and estimated net savings, and download the revised repayment schedule CSV.
Limitations and Notes
- The calculation assumes that the prepayment is processed immediately after the scheduled payment for period N is credited; interest calculated on non-payment dates, minimum amounts, limits on the number of payments, and bank approval rules must be confirmed with the lending institution.
- Current-period interest and penalty fees must be entered by the user according to the institution’s standards; the tool will not infer Actual/360, Actual/365, monthly interest calculations, or contractual penalty formulas.
- The result is a static estimate based on a fixed interest rate and a monthly integer-amortization repayment plan. It is not a bank quote, approval commitment, contract interpretation, or settlement statement.
FAQ
Which point in time should the number of repaid periods represent?
Enter the number of scheduled periods that have already been successfully posted; for example, entering 60 means that period 60 has been repaid, and early repayment occurs immediately afterward.
Why are the monthly payments not exactly the same when shortening the term?
The tool finds the shortest whole number of months for which the initial payment is no greater than the original next payment; rounding to cents each month may cause slight differences.
Why is the principal repaid early not counted as a fee?
It reduces the loan balance, not an additional loss; net estimated savings are calculated by deducting the current-period interest and penalty from the gross interest savings.