Loan Calculator

This tool computes a fixed-rate amortizing loan's monthly payment, total payment, and total interest, and generates a full month-by-month amortization schedule. It supports entering the term in years or months and an optional start month that is used to date each payment row.

1. Enter Loan Amount (principal, e.g. 100000). 2. Enter Interest Rate as an annual percentage (e.g. 5.5 for 5.5%). 3. Enter Loan Term and pick years or months. 4. Optionally pick a Start month (type=month) to add a Date column. 5. Click Calculate. Use Show / Hide Schedule to expand the amortization table; Reset clears the form.

Monthly rate r = annualRate / 100 / 12, n = total months (years are multiplied by 12, rounded). When r > 0 the monthly payment uses the standard annuity formula: M = P × (r × (1+r)^n) / ((1+r)^n − 1). When r = 0 it falls back to M = P / n. Total payment = M × n; total interest = total payment − principal. Each month: interest = balance × r, principal paid = M − interest, new balance = max(0, balance − principal paid). A 0% rate is supported; negative rate, term, or principal are rejected.