Does an employee have to give a certain amount of his salary in zakaah?
Question

                Is there a set amount that the employee must give of his salary as charity for the sake of Allaah? If that is not the case, what is the amount that it is recommended to give in charity?.
Praise be to Allah.If a person 
    owns the minimum threshhold of wealth (nisaab), of gold or silver, or money 
    saved from his salary or otherwise, and one full hijri year has passed, then 
    he must pay zakaah on it, by giving one-quarter of one-tenth of it, or 2.5%. 
    The nisaab is the equivalent of 85 grams of gold or 595 grams of silver. 
For 
    information on how to pay zakaah on one’s salary, please see question no. 
    26113. But if an employee does not have to pay zakaah on the salary that he 
    gets every month because one full hijri year has not passed since he took 
    possession of the nisaab, then there is no set amount of the salary that he 
    has to give in charity, but he should not deprive himself of the reward of 
    charity. So he should give in charity whatever he can. Allaah says 
    (interpretation of the meaning): 
“The 
    likeness of those who spend their wealth in the way of Allaah, is as the 
    likeness of a grain (of corn); it grows seven ears, and each ear has a 
    hundred grains. Allaah gives manifold increase to whom He wills. And Allaah 
    is All-Sufficient for His creatures’ needs, All-Knower”

    [al-Baqarah 2:261] 
“If you 
    disclose your Sadaqaat (almsgiving), it is well; but if you conceal them and 
    give them to the poor, that is better for you. (Allaah) will expiate you 
    some of your sins. And Allaah is Well-Acquainted with what you do”

    [al-Baqarah 2:271] 
“Verily, 
    those who give Sadaqaat (i.e. Zakaah and alms), men and women, and lend 
    Allaah a goodly loan, it shall be increased manifold (to their credit), and 
    theirs shall be an honourable good reward (i.e. Paradise)”

    [al-Hadeed 57:18]
The Prophet 
     (peace and blessings of Allaah be upon him) said: “Whoever gives in 
    charity the equivalent of a date earned from a good (halaal) source – for 
    Allaah does not accept anything but that which is good – Allaah will take it 
    in His right hand and tend it for its giver as one of you tends his colt, 
    until it becomes like a mountain.” Narrated by al-Bukhaari (1410) and Muslim 
    (1014). 
And the 
    Prophet  (peace and blessings of Allaah be upon him) said that one of 
    the eight gates of Paradise is the gate of Charity, and everyone who gave 
    charity will enter through it. Narrated by al-Bukhaari(1897) and Muslim 
    (1027). 
And he  
    (peace and blessings of Allaah be upon him) said: “The best of charity is 
    that which is given when one can afford it, and start with those who are 
    under your care.” Narrated by al-Bukhaari (1426)and Muslim (1034). 
What is 
    meant is that the best of charity is that after which the giver remains 
    independent of means because of that which he has left with him. That means 
    that the best of charity is that after which enough wealth is left for the 
    giver to depend on and spend on his interests and needs. This is the best of 
    charity, better than one who gives all his wealth in charity, because the 
    one who gives all his wealth in charity usually regrets it or he may regret 
    it if he finds himself in need, and he may wish that he had not given 
    charity, unlike the one who still has enough to keep him independent of 
    means; he will not regret it rather he will rejoice in it… “And start with 
    those who are under your care” means that he should give priority to himself 
    and his dependents. End quote from Sharh al-Nawawi ‘ala Muslim. 
Ibn Qudaamah 
    (may Allaah have mercy on him) said: 
Giving 
    charity in secret is better than giving charity openly, because Allaah says 
    (interpretation of the meaning):  
“If you 
    disclose your Sadaqaat (almsgiving), it is well; but if you conceal them and 
    give them to the poor, that is better for you. (Allaah) will expiate you 
    some of your sins”

    [al-Baqarah 2:271]
Abu Hurayrah 
    (may Allaah be pleased with him) narrated that the Prophet  (peace and 
    blessings of Allaah be upon him) said: “There are seven whom Allaah will 
    shade in the shade of His Throne on the Day when there will be no shade but 
    His,”… and he mentioned a man who gives charity and conceals it to such an 
    extent that his left hand does not know what his right hand is doing. Agreed 
    upon. 
It is 
    mustahabb to give a great deal of charity at times of need, because Allaah 
    says (interpretation of the meaning): 
“Or 
    giving food in a day of hunger (famine)”
[al-Balad 
    90:14]
And it is 
    mustahabb to give charity during the month of Ramadaan, because the reward 
    for good deeds is multiplied therein, and because it is helping people to 
    observe the obligatory fast. The one who gives food to a fasting person to 
    break his fast will have a reward like his. 
It is 
    mustahabb to give charity to relatives, because Allaah says (interpretation 
    of the meaning): 
“To an 
    orphan near of kin”
[al-Balad 
    90:15]
i.e., this 
    combines the two virtues of giving charity to orphans and relatives. The 
    Prophet  (peace and blessings of Allaah be upon him) said: “Charity 
    given to a poor person is charity, but given to a relative it is both 
    charity and upholding the ties of kinship.” This is a hasan hadeeth. 
It is 
    mustahabb to give charity to one who is in severe need, because Allaah says 
    (interpretation of the meaning): 
“Or to a 
    Miskeen (poor) cleaving to dust (out of misery)”
[al-Balad 
    90:16]
i.e., he has 
    nothing in his hand but dust, in other words he is very poor indeed. 
End quote 
    from al-Mughni (2/368) 
See also 
    question no. 6266 and 
    22881. 
And Allaah knows 
    best.