See exactly how every extra dollar you chip in cuts down your interest and gets you to that final payment sooner.
Understanding Our Math
This section describes how the calculator analyzes and applies your loan information.
Monthly Payment Formula
Your monthly payment is calculated using the standard loan amortization equation:
M = P × [r(1 + r)ⁿ] / [(1 + r)ⁿ − 1]Where:
- M = Monthly payment
- P = Loan principal
- r = Monthly interest rate (annual rate ÷ 12)
- n = Total number of payments (loan term in years × 12)
Interest & Principal Breakdown
Each payment is split into the following parts:
- Interest = Remaining balance × monthly interest rate
- Principal = Monthly payment − interest
- New Balance = Previous balance − principal
How Extra Payments Help
Any additional payment goes directly toward the principal, which:
- Reduces the balance faster
- Lowers the total interest paid
- Shortens the overall loan term
- Can lead to significant long-term savings
Payment Frequency Options
For comparison purposes, all payment schedules are converted to monthly equivalents:
- Monthly = 1 payment per month
- Bi-weekly ≈ 2.17 payments per month (26 ÷ 12)
- Annual = 1 payment per year
References
This calculator is based on:
- Standard amortization principles
- Consumer Financial Protection Bureau (CFPB) guidance
- Federal Reserve interest rate standards
Note: Results are estimates only. Actual payments may vary depending on lender policies, fees, and payment timing.