According to the day the zakat was due in.

I calculated the value of zakat that i had to give and it turned out to be 40000 rupees so i put this money aside. Few days later when i was about to hand over the zakat money, the rate of gold had changed and the due zakat now turned out to be 50000 rupees. At what rate do i give the zakat? According to the day i calculated it or the day when i hand over the money?

Zakat |