Is it permissible for a Muslim to take the inflation rate from the bank and donate the rest?

The Islamic Fiqh Academy has decided that what matters in the fulfillment of debts fixed in a certain currency is the like [of the amount owed], not the value; because debts are repaid with their likes, and it is not permissible to link them to the level of prices. Accordingly, inflation does not change the ruling on a loan and a bank deposit. You are only entitled to your principal, and you should give the rest in charity or spend it on charitable causes.