Answered by Faraz Rabbani
Question: I had missed fasts which I did not make up before the next Ramadan began. Have I missed my opportunity to make them up and do i know have to pay fidya? What if I had an excuse?
Answer: In the Name of Allah, Most Gracious, Most Merciful.
In the Hanafi school, a person simply has to make up those missed fasts, when able, and no expiation (fidya) is required. [Ibn Abidin, Radd al-Muhtar; Ibn al-Humam, Fath al-Qadir]
The details of this are:
(1) If you miss a fast, you must make it up. This duty is not lifted if you fail to make it up before the next Ramadan.
(2) The duty is to actually make up one’s missed fasts. Unless one is elderly and permanently unable to fast, one can’t give expiatory payments instead.
(3) If unsure about how many fasts one missed, one should make a reasonable-yet-conservative estimate. The general principle is that when certainty is not possible, one resorts to reasoned judgment. [Ala' al-Din Abidin, al-Hadiyya al-`Ala'iyya]