Analyze how paying extra accelerates loan payoff
Calculation Methodology
Monthly Payment Formula
Payments are computed using the traditional amortization formula:
M = P × [r(1+r)^n] / [(1+r)^n – 1]- M: Monthly required payment
- P: Loan principal
- r: Monthly rate (annual interest / 12)
- n: Count of total payments
Interest Calculation
For every month:
Interest = Loan Balance × Monthly Rate
Principal = Payment – Interest Amount
Adjusted Balance = Loan Balance – PrincipalPrepayment Impact
Any extra payment goes directly to principal, reducing the amount of interest charged in the future. This compounding effect shortens payoff time and substantially reduces total interest paid.
Lump Sum Payment
A lump sum at a chosen month is fully applied to principal, creating an immediate drop in balance and future interest obligations.
References
- Common Amortization Calculations
- CFPB Loan Calculation Information
- Federal Reserve Lending Policies
Disclaimer: Figures are estimated using your inputs. Lender rules, fees, and policies may change actual outcomes. Confirm with your lender for accuracy.