Zakah is not due on what is less than five ounces, nor on what is less than five camels, nor on what is less than five Wasqs
Authentic hadithعن أبي سعيد الْخُدْرِي رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «ليس فيما دون خمس أَوَاقٍ صدقة، ولا فيما دون خمس ذَوْدٍ صدقة، ولا فيما دُونَ خمسة أَوْسُقٍ صدقة».
Abu Sa‘īd al-Khudri (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Zakah is not due on what is less than five ounces, nor on what is less than five camels, nor on what is less than five Wasqs."
Explanation
Zakah is a means of support given by the rich to the poor. Hence, it is not due on anyone who is not rich or has enough resources. Allah, the Almighty, has stated the minimum amount on which Zakah is due. Anyone owns less than the minimum amount is considered poor, and nothing is to be taken from him. Thus, no Zakah is due on the owner of silver unless he has five ounces. Likewise, no Zakah is due on the owner of camels unless he has five camels or more. There is no Zakah on less than five camels. Finally, no Zakah is due on the owner of grains and fruits unless he has five Wasqs (total of 300 Sā‘s).
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).