Interest Rate Calculator is an online personal finance assessment tool to calculate interest rate for either compond interest or simple interest. The principal, maturity period and final return are the key components to compute the interest rate over time, Simple and Compound interest are possibly the most important concept in financial market when it comes to successful long or short term investing or lending or borrowing. Interest is a fee paid on borrowed assets. It is the price paid for the use of borrowed money or money earned by deposited funds. Compound interest arises when interest is added to the principal, so that from that moment on, the interest that has been added also itself earns interest. This addition of interest to the principal is called compounding. Simple interest is calculated only on the principal amount, or on that portion of the principal amount that remains unpaid. By using this calculator you can determine both simple and compound interest calculation. Select an appropriate radio butto to perform the right calculation