Bank loan is a contract by which a credit institution lends a certain amount of money to the debtor with the requirement that the borrowed money, increased by the price (interest), must be repaid within a certain period of time. The price of borrowed money, interest, is expressed as a nominal interest rate. Granting a loan requires from the borrower additional costs and demands, such as, for example, loan approval fee, insurance policies, etc., which increases the price of the loan. That is why credit institutions are obliged to present the effective interest rate in their credit offers. The effective interest rate shows the total cost of the loan. It is calculated in a uniform way and, in addition to the nominal interest rate, the calculation of this interest rate also includes fees charged when the loan is granted. This final thesis shows how the effective interest rate facilitates the comparison of the loan offers between different credit institutions. It is shown that choosing a more affordable loan can be based on a comparison of effective interest rates, but also that, in order to make a final decision, it is important to check all the conditions and requirements of the loan agreement.