Fidyah is the donation that compensates for Ramadan fasts a person misses through a continuing necessity or inability to make them up.
The term generally refers to providing food or its monetary equivalent for people in need. It applies, for example, when someone is permanently unable to fast because of advanced age or a lasting illness. In some circumstances involving pregnancy or health, the applicable ruling can depend on the person’s condition and the Islamic legal school followed.
Fidyah is usually calculated for each missed fast, but the amount and acceptable form vary by jurisdiction and scholarly interpretation. Someone who is temporarily ill or travelling and later becomes able to fast generally makes up the missed days instead; fidyah is not simply an alternative chosen for convenience.
The key distinction is between fidyah and kaffarah. Fidyah addresses inability or an excusing necessity, while kaffarah is an atonement associated with violating certain fasting obligations. Sadaqah is voluntary charity, and zakat is a distinct obligatory almsgiving system.