If you have missed paying your Zakat, whatever the reason, miscalculating or missing Zakat from previous years – whether intentional or unintentional – remains a debt to be paid and must be done so without delay. Otherwise, you risk destroying your own wealth as per the hadith:

“Zakat is never intermingled with any amount of wealth without destroying and rotting it.” (Bukhari)

Moreover, Zakat is a right of the poor and holding on to it will not only increase poverty in society but will also result in severe consequences for the individual concerned:

“When a slave of Allah pays Zakat, the Angels of Allah pray for him in these words: “O Allah! Grant abundance to him who spends (in Your cause) and destroy him who does not spend and restricts to himself his wealth.” (Bukhari)