In a general division, we may divide Islamic taxes into two main groups; the immutable and the mutable. The immutable include those determined by the holy lawmaker primarily and directly. The quantity, the proportion, and the items taxable are thoroughly determined. This group includes the following items:
The word zakat in Arabic comes from the root Zakawa meaning to grow and to purify. The Islamic religion pays close attention to zakat. In several Koran verses, zakat is mentioned after salat as two important religious services. According to the Koran and many hadiths, zakat is some money payable by an individual in order to purify him, help him with his deliverance, and help the needy financially. It brings about the betterment of one’s livelihood, increase of wealth, and economic security in society. There are two kinds of zakat; Fitr zakat and possession zakat. The former means that every individual who is not a slave or poor and is of age, of sound mental state, and sober must pay around three kilograms of wheat, rice, corn, barley, raisin, or similar food staff to the needy at the nightfall of the last day of the month of Ramadan for himself and for every individual whom he has to support financially. The latter means a percentage of the property one has must be paid as religious tax annually. Nine kinds of property are included among what must be taxed: wheat, barley, date, raisin, caw, sheep, camel, gold, and silver. The Koran mentions eight categories on which zakat must be spent: the needy, the poor, the taxmen, the promotion of affinity, the emancipation of slaves, the indebted, in the path of God, and those travelers who need help in order to get back home.
The second immutable tax is called khoms. The word khoms literally means one fifth. This tax is so called because the rate of taxation on seven specified items is twenty percent. They are: annual surplus profit, mining, treasure, legal money mixed up with illegal, the jewelry fished from sea by diving, booty, and the price of real property bought from a Muslim by a non-Muslim. A part of the expenses of the Islamic state is covered by khoms. Every individual in possession of these items is obliged to pay the tax with the intention to implement divine command. The Koran portions out this collected tax to six shares: one share is God’s, one share is Prophet’s, one share is allocated for the immaculate Imam, one share goes to the orphans, one share for the poor, and the last belongs to travelers who need help in order to go back home.
Jezyah  is the third kind of taxation. It is capitation on non-Muslims living within the jurisdiction of the Islamic state that protects them or living without but under its pledge of protection. The Koran defines this kind of taxation in verse no. 29 of Sura Tawbah. It is the right of the Muslim government to level the tax on individuals or on their estates and production as the situation requires. The amount payable is negotiable. This tax is in lieu of zakat and khoms which non-Muslims do not pay.
Kharaj is the fourth kind of tax that was collected from land. It constitutes a very important source of income for Islamic state throughout history. As Muslim conquests went on in early decades, the ownership of land underwent drastic changes. Four different types of land can be distinguished. In some cases, the inhabitants of a region accepted Islamic call freely and willfully. Their ownership of their property moveable or immovable was recognized. In some cases, they fought the Muslim army but were defeated. Their immovable property was confiscated. This type of land was called conquest (or maftuhato onwatan). Sometimes, the non-Muslim inhabitants entered into a peace agreement with the Muslim army. Their lands were called peace lands. The fourth kind of land was the one either abandoned by owners without fighting or left to the Islamic state by them or left unattended because the owners had perished. This type of land belonged to the state. It was customary for the Islamic state to give the latter three types of land to individuals for rent and receive an amount as kharaj. The rent due to be paid was fixed through negotiation and varied depending on the fertility and the kind and level of production expected.