Q. Is zakaat calculated only on income earned during a particular period of one year or is it calculated on incomes earned on previous years even though you paid zakaat on that income previously?
A. Zakaat will be calculated and paid on the entire savings. This includes that of the previous years and that of the current year. Even though you may have paid zakaat already in the past year on a certain sum, you will have to pay again on that sum if it is still with you.
And Allah knows best.
Mufti Waseem Khan