The Prophet ﷺ said: "Whoever fasts Ramadan then follows it with six days of Shawwal, it is as if he fasted the whole year." Because the wording is "fasts Ramadan then follows it," many scholars — including Ibn 'Uthaymin and the Permanent Committee for Islamic Research and Iftaa — hold that the obligatory make-up days must be completed first, since one has not truly "fasted Ramadan" until the debt is paid. Others, including the Hanafis and Shafi'is, permit the six voluntary days first — especially for a woman with many days to repay — because qada' is not required immediately and has a wide window, while the six days are restricted to the month of Shawwal. 'A'ishah رضي الله عنها said she used to have make-up days from Ramadan that she could not fast until Sha'ban, which shows the wide window for qada'. This is a genuine and respectable ikhtilaf, so no one should be criticised for either practice; the safer course, and the stronger view, is to finish the make-up days first — and the six days may then be fasted consecutively or spread across Shawwal.
Q&A · Fasting
Must I make up my missed Ramadan days before fasting the six days of Shawwal?
Evidence — the daleel
Sahih Muslim 1164 ṢaḥīḥSahih al-Bukhari 1950 Ṣaḥīḥ
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.