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Results will appear here
Results
Annual Interest Rate (APR)
Total Interest Paid
How to Use
- Enter Loan Amount: Input the total principal amount of the loan.
- Enter Loan Term: Input the total number of months for the loan (e.g., 360 for 30 years).
- Enter Monthly Payment: Input your fixed monthly repayment amount.
- Calculate: Click the 'Calculate Rate' button to determine the actual Annual Percentage Rate (APR).
- View Results: The calculated annual interest rate and total interest paid will be displayed below.
Tips & FAQ
Calculation Method: Since the interest rate cannot be isolated algebraically, this tool uses numerical approximation (like the Newton-Raphson method) to find the exact rate.
Core Formula: Based on the amortization formula M = P × [ r(1 + r)^n ] / [ (1 + r)^n - 1 ], solving for r iteratively.
Input Requirements: Ensure the monthly payment is high enough to cover the principal (total payment must exceed loan amount), otherwise a valid rate cannot be calculated.
Privacy: All calculations are performed locally in your browser. Your financial data is never uploaded to any server.
