Questions: Could you please explain the source of the figure of 2.5% regarding zakat? I am of the opinion that this figure can be changed according to the requirements of time. And also the nisab (85 grams gold or 595 grams silver) is also not a fixed amount till the Day of Judgment; it can also vary according to the need of the time. If the value of silver is taken as nisab, then this amount is about 10,000/- yens (or 5000 Pakistani Rupees). This definition of nisab makes almost everyone in Pakistan 'rich' which means that zakat can only be paid to the government and not to any individual (as a sahib-i- nisab can not receive zakat money). 
    Answers: Your questions need some elaboration:
    Islam has been given to the Ummah by the Prophet (sws) through the consensus of his companions and through their perpetual practice and perpetual recitation in two forms:
 
    1. The Qur’an
    2. The Sunnah
 
    Whilst it is clear what the Qur’an is, by Sunnah is meant that tradition of the Prophet Abraham (sws) to which the Prophet (sws) gave religious sanction among his followers after reviving and reforming it and after making certain additions to it. The Qur’an has directed the Prophet (sws) to obey this Abrahamic tradition in the following words:

Then We revealed to you to follow the ways of Abraham, who was true in faith and was not among the polytheists. (16:123)

    Zakat and its rates have been given to us through this Sunnah and cannot be changed. They have existed since the very beginning. Even Judaism and Christianity, the divinely revealed religions which followed the Abrahamic tradition and which preceded Islam, mention the same rates of Zakat as are upheld by Islam. 
    There are certain other premises about zakat also which need to be understood and which, I am afraid, seem to have disappeared in current times.
    It is the only tax an Islamic government can impose upon its Muslim citizens. Therefore, a person can only give it in his personal capacity if the government is not collecting it. It is not merely a charity fund. It can be spent on the collective needs of the people as well: The zakat money can be used to pay the salaries of government officials including the salary of the head of state, to build all works of public interest, to cater for defence requirements and to establish an Islamic system of insurance. 
    The notion that he zakat money cannot be given to a sahib-i-nisab is totally baseless. The following Qur’anic verse spells out the heads under which the zakat fund can be expended:

Zakat is only for the poor and the needy, and for those who are ‘amils over it, and for those whose hearts are to be reconciled [to the truth], and for the emancipation of the slaves and for those who have been inflicted with losses and for [spending in] the way of Allah and for the wayfarers. (9:60)

    A brief explanation of these heads follows:
    1) The Poor and Needy (Fuqara and Masakin): The poor and the needy are the foremost recipients of zakat because they are the primary responsibility of the state. It must cater for their basic needs like food, clothing, shelter, health and education.
    2) The ‘Amils over Zakat (‘amilina ‘alayha): Under this head, the salaries of all employees of the government which run and manage a state can be paid. 
    3) Those whose hearts are to be reconciled (Muallafatu’l Qulub): Under this head come all forms of political expenditure in the interest of Islam. There are may be many instances, when the affection of certain influential people must be obtained, particularly in border areas where their role can be decisive in the safety of a country. During the time of the Prophet (sws) many tribes were given money under this head to deter them from harming the newly founded Islamic State.
    4) Slaves (Riqab): The institution of slavery was totally eliminated by Islam fourteen centuries ago. From this particular head money was given to free slaves. Today, by analogy, this head can be extended to include other recipients. For example, prisoners of war and other prisoners who are unable to pay the fine imposed by the courts can be freed by giving money through this head.
    5) Those inflicted with losses (Gharimin): Under this head, an Islamic system of Insurance can be established and all those who are inflicted with economic losses can be compensated. Whether rich or poor the real criterion is that their means of living and its role in the national economy have been destroyed. People who have acquired a loan and are unable to pay it back may also be helped from this money so that they may start afresh and the society can benefit from their abilities.
    6) In the Way of Allah (Fi Sabilillah): Under this head, expenditures of all kinds which serve the cause of Islam and the welfare of people like defence requirements, religious propagation, educational institutions, mosques, libraries and hospitals can be made.
    7) The Wayfarer (Ibn al-Sabil): This implies the welfare of the wayfarer. Circumstances often make a traveller a needy person, in which case, his needs can be fulfilled from this head. Also roads and bridges can be constructed. 
    As far as the nisab (exemption) of zakat is concerned, it only means that no zakat can be collected below this amount. The nisab rate can be increased by an Islamic state if required. Also, the actual yardstick in calculating the nisab is silver and not gold or both as is generally held. This misconception seems to have arisen from the equation that existed between silver and gold (7.5 tolas of gold = 52.5 tolas of silver) in the times of the Prophet (sws).