Our late mother used to pay annual Zakah from her estate, but we have doubts concerning the paid percentage of Zakah she used to give

Q: My mother (may Allah be merciful to her) died and left a sum of money. All the inheritors, who are adults, have relinquished their shares in the estate and decided to donate it to charitable projects for the sake of our late mother (may Allah be merciful to her). She used to pay annual Zakah (obligatory charity) of this estate which was collected throughout her life. However, we - the children - have some doubts concerning the paid percentage of Zakah she used to give, whether it was exactly 2.5% or a roughly estimated percentage. How should we pay Zakah of the money which we now possess? How many years should we pay Zakah on her behalf before we spend the estate on charitable projects? A: If the case is as you have mentioned, that all of you as inheritors are adults and there is no one of minor age among you, and you have agreed to spend the estate of your mother on benevolent projects, (Part No. 8; Page No. 205

A: If the case is as you have mentioned, that all of you as inheritors are adults and there is no one of minor age among you, and you have agreed to spend the estate of your mother on benevolent projects, (Part No. 8; Page No. 205) then, there is no Zakah due on it. Regarding the doubt on the mother's payment of Zakah in her life, there is no basis for this doubt and you need not to take any further action regarding it.May Allah grant us success. May Peace and Blessings of Allah be upon our Prophet Muhammad, his family and his Companions!