About the Amortization Calculator
See exactly how each repayment is split between interest and principal and how your balance falls over time — by year or payment by payment.
How does the Amortization Calculator work?
Each period, interest is charged on the remaining balance. The rest of the fixed repayment reduces the balance, so the principal portion grows every period.
Amortization Calculator formula
interestₖ = balanceₖ₋₁ × r
principalₖ = PMT − interestₖ
balanceₖ = balanceₖ₋₁ − principalₖ