I Earned a Large Amount of Cash a Few Days Before the Zakat Year was up, Do I Pay Zakat on This Amount Now, or After a Year has Passed From When I Received it?
Example: Talha's zakat year begins on the 5th of Safar. On the 25th of Muharram, only a few
days before his zakat year elapsed, he was given a gift of £3000. Ten days later, when the 5th of Safar
comes around, he has to pay £75 in zakat.
You pay zakat when the zakat year has elapsed, irrespective of when particular portions of your wealth came into your possession. Even if the cash came into your possession a day before the zakat year had elapsed, you would have to pay zakat on it the following day.