Interest Rate Calculator Don't know what interest rate your are paying on a loan?  Fill in the form below and we will calculate it.  This calculator is for loans with fixed payment periods; such as home or auto loans. Original Loan Amount: Monthly Payment (do not include escrow accounts or any other charges): Loan Term : Years Months Powered by yourmoneypage.com.  This calculator is provided as a free service. No guarantee, explicit or implied, is made regarding its' accuracy or suitability to a specific purpose.