The non-muslim subjects in an Islamic States are levied a tax which is termed Jizya in Shariah in lieu of the tax levied on the Muslim subjects in the same State which is termed Zakaah in Shariah. 
جِزْيَة ( اسم ) : ضَرِيبَة
- tax or payment of the same amount from each person
- money paid as part of a special transaction
- sum of money paid as a tax; imposing or paying taxes
- an amount of money that you must pay to the government according to your income, property, goods etc.
- tax levied at the same rate on every person in the community
- a charge payable for permission to pass a barrier or use a bridge or road etc.
- a payment of goods or money by one ruler or country to another more powerful one .
- with payment for goods to be made after they have been sold by the receiver 
Jizya is a tax collected on a section of an Islamic state's non-Muslim subjects, who meet certain criteria. The tax is to be collected on able-bodied adult males of military age (but with specific exemptions).
Jizya is a material proof of the non-Muslims' acceptance of subjection to the state and its laws. In return, non-Muslim subjects are permitted to practice their faith, to enjoy a measure of communal autonomy, to be entitled to the Muslim state's protection from outside aggression, and to be exempted from military service and from the zakat tax collected upon Muslim citizen 
Jizya or poll tax had been in vogue since before the advent of Islam. The Greeks are reported to have imposed a similar tax upon the inhabitants of the coastal regions of Asia Minor during 500 B.C. The Romans imposed similar taxes upon the people they conquered, and the amount was much heavier than what was later imposed by the Muslims. The Persians are also reported to have introduced a similar tax upon their subjects.
According to Shibli Nu'mani, the word Jizya itself is the Arabicised version of the word Kizyat, meaning a levy which the Persian rulers used to employ in administering the affairs of war. He further indicates that this term was either in currency in both the languages, or the Arabs adapted it from the Persian language.
Whatever the case, it is certain that the Arabs first knew about this tax from the Persians. The Sasanid emperor Nawsherwan is reported to have introduced a tax, upon his subjects also termed as Jizya by the Arab historians, with the exemption of the nobility, satraps, military personnel, secretaries and those in the service of the emperor, at the varying rates of 12/8/6/2 dirhams upon each person. 
Jizya was not introduced until around the battle of Tabuk in the 8th year of the Hijra when the Quran Surah Taubah 9:29 was revealed.
The Charter of Medina, or ‘The Saheefah’ which may be called the Magna Carta for the foundation of the Islamic state at Medina, decreed by the Prophet ﷺsoon after his migration, does not contain any provision for Jizya or any other regular taxes. It is certainly the basic and historical document to determine the status of non-Muslim inhabitants in an Islamic State. And the tax of Jizya, in its popular notion, unquestionably has a deep involvement with the status of non-Muslims in a Muslim state. 
With the conquests of Mecca in the 8th Hijri, and, soon after, of Tabuk, almost all the forces that could have been a factor in challenging the authority of the Muslims were subdued. The expedition of Tabuk, in particular, frustrated a major Roman onslaught upon the Muslims. The Christian principalities bordering the Syrian regions were now compelled to think in arriving at some political settlement with the undisputed authority of the Prophet. They agreed to pay Jizya and were granted complete protection of their life, property and religion.
Similarly, during this period, a large number of deputations of different Arab tribes and clans came to the Prophet ﷺand offered their allegiance by embracing Islam. They were promised protection of life and property on the understanding that they would faithfully obey the Islamic tenets.
The Prophet ﷺmade covenants and executed agreements with the tribes of both Muslims and non-Muslims. A comparative and analytical study certainly helps us to delineate the objectives underlying the imposition of Jizya. It can be noticed that in none of the covenants and agreements, the terms offered to the Muslims were dissimilar to those offered to the non-Muslims, except that the former were required to prove their allegiance by faithfully performing the Islamic tenets (including the payment of Zakat) and the non-Muslims by the payment of Jizya.
By guaranteeing all protection in unabmiguous terms to the members of the Christian monastery and the Jewish Rabbinate, all possibilities of alluring the respective communities to convert to Islam were annulled. It also does not appear that those converted to Islam were accorded any privileged status over those who retained their previous faith, nor does it appear that the non-Muslims who were to pay Jizya were, for the matter, burdened with any humiliating provisions.
As against their submission to the authority of the Prophet ﷺ, both Muslims and non-Muslims were guaranteed the same protection of Allah and His Prophet for their persons, properties and performance of religious rites.
It is worth noticing that the security under the protection of Allah and His Prophet was guaranteed to both communities, Muslims and non-Muslims in the same phraseology and in the same spirit. 
The covenants made by the Prophet ﷺwith non-Muslims continued to remain in force in subsequent times. The Christians of Najran got the Prophet's ﷺcovenants with them renewed with the same terms and almost in the same language by Abu Bakr(R), and the later Caliphs.
The Christians of Najran, however, had to be deported by 'Umar(R) from the Yemen to Kufa for their subversion against the State and for their indulgence in usury. Inorder to discharge the responsiblity of dhimma guaranteed to them by the Prophet(R), the second Caliph, with a provision of the exemption of Jizya for two years, even ordered for them the grant of sufficient lands in Iraq or Syria wherever they wished to settle.
With a view to fulfilling the obligation of dhimma, 'Uthman (R) went a step forward with a further cut in the amount of Jizya when he found that the amount imposed by his predecessor was not favourable to them. 'Ali (R) is reported to have continued all the favours accorded to them so far. 
Not all Thimmis are required to pay Jizyah; Jizyah is levied only on adult, free, sane men from the People of the Book who are able to fight and able to pay the Jizyah.
It is not levied on women, children, slaves, mad people, the senile or elderly, or the destitute who are financially unable to afford it (they were exempted from it). Note that the amount of Jizyah is significantly small. Muslims may pay more than the amount of Jizyah in Zakaah, and, therefore, Muslims are exempted from paying the Jizyah; Muslims are only obliged to pay the Zakaah. 
Some contemporary Muslim scholars, like Dr. ‘Abd Al-Kareem Zidaan, held that the preponderant opinion is that Jizyah is levied in exchange for providing protection for the Dhimmis and defending their safety; hence, it is cancelled when they join the military service and participate with Muslims in defending the Islamic state against its enemies.
Dr. Zaidaan wrote, “The Thimmis who join military service of the Islamic state and defend the Islamic state against its enemies are exempted from paying Jizyah. Participating in defending the Islamic state entails exempting the Dhimmis from the payment of Jizyah or cancels the obligation of imposing it in the first place, as we saw in the historical incidents that we mentioned.” Ahkaam Ath-Thimmiyyeen wa Al-Musta’maneen fi Daar Al-Islam 
The calculation of the Zakaah tax varies from product to product (agriculture 5%-10%, rental 10%, etc.), but the general tax on wealth is calculated at 2.5% per annum on the net worth of the person. There is no fixed calculation of the Jizya tax, as the calculation is determined by the State depending on the situation and period. 
During the reign of the second caliph, ‘Umar bin al-Khattaab, may Allaah be pleased with him, the Roman emperor, Heraclius, raised a huge army to repel the Muslim forces. It was, thus, incumbent upon the Muslims to concentrate their efforts on the battle. When the commander of the Muslims, Abu ‘Ubaydah, may Allaah be pleased with him, heard this news, he wrote to his officials in all conquered cities in Syria and ordered them to return the Jizyah which had been levied in those cities.
He also addressed the public saying; “We are returning your money because we know that the enemy has gathered troops. By the terms stipulated in the covenant, you have obliged us to protect you. However, since we are now unable to fulfil these conditions, we have returned to you what you paid to us. We shall abide by the terms agreed upon in the covenant, if Allaah helps us to rout the enemy”. Thus, a huge amount was taken from the state treasury and returned to the Christians, making them very happy. They prayed for and blessed the Muslim commanders.
They exclaimed: “May Allaah help you to overcome your enemies and return you to us safely. If the enemy were in your place, they would never have returned anything to us, rather they would have taken all our remaining property. 
One of the problems raised by missionaries and orientalists is the imposition of the Jizya on all non-Muslims. This institution has been so misinterpreted and misexplained that the Non-Muslims feel that it is some kind of religion-based discrimination against them.
All the Jizya amounts are to be a financial obligation placed upon those who do not have to pay the Zakaat. As the ratio of these two taxes is the same, it is obvious that the Jizya is simply a technique used by Islamic governments to make sure that everyone pays his fair share. If the term 'Jizya' is too offensive to non-Muslims, it can always be changed: ‘Umar bin Al-Khattaab, may Allaah be pleased with him, levied the Jizya upon the Christians of the Bani Taghlib and called it Sadaqah (alms) out of consideration for their feelings.
In his covenant with the people of certain cities near Al-Hayrah, Khaalid bin Al-Waleed, may Allaah be pleased with him, recorded: “If we are able to protect you, we deserve the collection of Jizyah; otherwise, we shall not offer you protection." 
Allah's Messenger (ﷺ) said, "The Hour will not be established until the son of Mary (i.e. Jesus) descends amongst you as a just ruler, he will break the cross, kill the pigs, and abolish the Jizya tax. Money will be in abundance so that nobody will accept it (as charitable gifts). Sahih al-Bukhari 2476