How it works
Build a fixed-rate amortization schedule showing payment, interest, principal, and balance.
Enter the loan amount, annual rate, and term. The calculator computes the equal monthly payment and breaks every payment into the interest and principal portions until the balance reaches zero.
Formula
M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1); interest each month = balance × r; principal = payment − interest.
P- Loan amount (currency)
r- Monthly interest rate (annual % / 12)
n- Number of monthly payments (months)
Examples
- 100,000 at 6% over 30 yearsLoan amount 100,000 · rate 6% · term 30 yearsMonthly payment ≈ 599.55 · total interest ≈ 115,838.19
Frequently asked questions
How does paying extra help?
Extra payments reduce the balance faster, which reduces future interest and shortens the loan. This version models the standard schedule without extra payments.
Why is most of the first payment interest?
Interest is charged on the outstanding balance. Early on the balance is largest, so interest dominates the payment.
How to read the result
Early payments are mostly interest; later payments are mostly principal. Total interest is the full cost of borrowing over the term.
Limitations
Fixed-rate, equal-payment loans only. Does not model extra/non-recurring payments, variable rates, or fees.
Source: Fixed-rate amortization schedule (standard consumer-credit formula).