What invalidates the fast and necessitate qada?
The fasts broken due to legal excuses like journey, old-age, illness necessitate only qada. Besides, eating and drinking without meaning it; eating or drinking things which are not meant for nourishment, and which are not habitual to partake and that human nature is not inclined to eat invalidate the fast and necessitate only qada. Unobserved fasts during Ramadan without excuses should be redeemed for the same number of days. However, the Prophet (pbuh) said that a person who lost a day without fasting in Ramadan could not attain the same reward even if he fasted the whole year. For this reason, quitting the fast without an excuse during Ramadan is a great sin and it is also a disrespect for Ramadan and for all Muslims. Not fasting without an excuse is a great sin and it necessitates repentance and supplication for forgiveness. Ramadan is an opportunity for forgiveness of sins. Fasts that are observed on other days are not the same as the fasts observed during Ramadan in terms of value
