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

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.