What is the amount of zakat due on a savings account of EGP 120,000, for which zakat has not been paid for 30 years, knowing that the account was opened in the questioner's name by his mother, who passed away shortly after its establishment?

Funds deposited in usurious banks must be disposed of, and the interest should be given as charity to the poor and needy or used for the benefit of Muslims. As for the principal, zakat (definition) must be paid on it for all past years, along with sincere repentance for delaying zakat. Zakat is calculated by giving one-quarter of one-tenth of the principal if it reaches the nisab (definition) (minimum threshold) in every Hijri year. If you cannot ascertain with certainty the exact amount that must be given, then act based on your best estimation (taharry) and give what absolves your responsibility.