What is the difference between Zakāt and Zakāt al-Fitr?
The Zakāt described above is the yearly 2.5 percent on the wealth you have built up, known as Zakāt al-mal. Zakāt al-Fitr is separate. It is a small fixed amount given on behalf of every member of the household at the end of Ramadan, before the Eid prayer, and it is due whether or not a person has wealth. Zakat Simple calculates Zakāt al-mal, the yearly Zakāt on your wealth.
Where this comes from
Zakat Made Easy, Mufti Faraz Adam: the position this app follows, used with the author's permission.