inflation rate vs interest rate on calculating present value of future money i use the formula 100/(1+r)^T to calculate the present value of my future money while r is interest rate and T is year.
However , for my country , interest rate (year) = %8.25 and inflation rate (year) = %12.60
Is it logical if i use inflation rate instead of interest rate at my calculation?
The question has some ambiguity. If you want to calculate something, you need to define what you are interested in. If you want to think in terms of purchasing power, you can use the inflation rate.
However, using inflation would be the wrong answer in the context of finance or project analysis. In the financial context, you are comparing money now versus money in the future. The basis of comparison is an instrument that bridges money from the present to the future, which are debt instruments.
For example, if you are borrowing to finance a project, your profitability depends on the return of the project in nominal terms versus the cost of financing. What the value of the currency does versus a basket of goods during that time does not matter.
The idea of inflation trading off future returns is a beloved concept of conventional economists, but its usefulness is greatly overrated. Since you cannot purchase the CPI basket and store it indefinitely, there is no obvious necessary relationship between inflation rates and the return on investable assets. (People might invoke model relationships, but that puts a lot of faith in the models.)