Question: When is one obligated to give zakat?
Zakat is given after it has become fard on a person. One who has reached nisab must write down the lunar date when one has reached it. For example, if one has reached nisab on Rajab 3, one must give zakat on Rajab 3 the following year if one still has money or trade goods reaching nisab. One does not have to wait for Ramadan to come to give zakat.
Similarly, there is nothing wrong with giving zakat before due date; it is better. One is even permitted to give zakat of the next few years in advance. If one calculates one's zakat wrongly and gives two gold coins instead of one gold coin before due date, one can deduct a gold coin from the zakat of the following year.
Some scholars say that one should give zakat within a year without hurrying up, but it is wajib to be in a hurry to give it immediately. It is makruh to delay it without an excuse. In the madhhabs of Shafii and Maliki, it is fard to give zakat immediately when it becomes fard on a person. A hadith-i sharif says, Hurry to give zakat (Ibn Majah).
Question: Is zakat given only in the month of Ramadan?
The month and the day zakat is due are different for every rich person, so one does not have to wait for Ramadan to give zakat. If one has reached nisab on, for example, Shawwal 23, one must give zakat on Shawwal 23 the following year. One is permitted to give it in Ramadan before the arrival of Shawwal, but in this case, one must calculate ones zakatable assets again when Shawwal 23 comes. If the amount one gave as zakat in advance is less than what is due, one must pay the deficit. If the amount one gave is more than what is due, the surplus is counted as nafilah. That is, it is permissible to give zakat in advance, but it is necessary to calculate ones zakatable assets again when ones zakat due-date comes.
Question: When a complete lunar year passes over the date when one has reached nisab, is it fard to give zakat right away? If one dies, is it necessary to give zakat from inherited money or property?
It is not necessary to give zakat as soon as it becomes fard on a person. Similarly, it is not necessary to pay it from inherited money or property if one dies before giving it. However, according to some scholars, it is makruh to delay giving zakat, and it is necessary to give it as soon as possible.
Question: If one cannot remember the date when one reached nisab, when should one give zakat?
One should designate a date by way of a strong opinion (zann-i ghalib), and then one should consider it ones zakat due-date.
Question: My zakat due-date is Ramadan 1. My wealth exceeds nisab. What time does zakat become fard on me on Ramadan 1?
A day, Islamically, starts at the time of imsak, so zakat becomes fard on you as of imsak.
Question: If my money or gold is stolen at noon on the date when I will give zakat, will I have to pay zakat later if I have money as zakat becomes fard after imsak?
No, you do not have to give it because it is not you who destroyed it.
Question: Suppose that ones zakat due-time has come, but one has not given zakat. Then one has become poor with no money. In this case, is one excused from the obligation of zakat?
If one oneself destroys ones zakatable assets, one will not be excused from the obligation of giving zakat. If it goes to destruction by itself, then one will be excused from zakat. That is, if one spends or destroys money oneself, one will not be excused from zakat. For example, if one loses all ones money in the stock market or spends it on goods, one will not be exempt from zakat but has to give it. If ones zakatable assets are stolen or lost or burnt to the ground or if one has loaned them but could not get them back, then it is not necessary to give zakat.
Question: What does destruction (halak) of nisab mean? Suppose that one gives zakat on Ramadan 27 every year. If ones zakatable assets go down below nisab before the arrival of Ramadan, should one determine ones zakat due-time afresh when one reaches nisab again?
No, one should not. Destruction (halak) of nisab means its falling to zero. It is considered to have gone destruction if it falls to zero or below zero. It happens by not having any money, gold, receivable, and zakatable assets or by getting into debt. Fluctuations during the middle of the year, unless one falls to below zero, are of no consequence even if one falls to below nisab. That is, these fluctuations do not change the date when one reached nisab. If one you mentioned in the question exceeds nisab on Ramadan 27 the following year, one must give zakat then. If one remains below nisab on that date, that date is cancelled as a complete year has passed. Then one should wait until one reaches nisab again. When one reaches nisab again, one should write down that lunar date. One must give zakat on that lunar date the following year if one still possesses nisab then. Decreases and increases during the middle of the year are of no consequence to ones zakat due-date. If one does not have nisab when a complete lunar year has passed, ones zakat due-date is canceled at the end of the year. Secondly, if ones wealth falls to below zero due to giving it away or getting into debt, then ones zakat due-date is canceled again, even if a complete lunar year has not passed yet, and one does not write down a date until one reaches nisab again.