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.