Based on the methodology of the investment effective interest rate (ESR), the formulas for calculating the profitability of the loan to the lender and costly for the borrower proposed. It is shown that the rate of internal rate of return that is used today by banks for these purposes is not a measure of profitability / costs on the loan. For the most common practice of credit schemes investigated the dependence of investment EPS of reinvestment rates and the main parameters of the loan – the term nominal interest rates, the rates of commission. The features of the definition and interpretation of investment EPS described. Practical recommendations for lenders and borrowers on the most effective credit schemes in the context of growing and declining interest rates proposed.