What is the ruling on fasting in the month of Shawwal? May one fulfill the missed fasts of Ramadan with the intention of Shawwal fasting?

Fasting for six days in the month of Shawwal after Ramadan is mustahab. The Prophet Muhammad (saw) said, “Whoever fasts Ramadan, then follows it with six from Shawwal, then that is (equal in reward) to fasting the whole year” (Muslim, Siyam, 204; Tirmidhi, Sawm, 53; Abu Dawud, Sawm, 59) This fasting may be performed consecutively or with breaks. (Ibn Abidin, Radd al-Muhtar, III, 421, 422).

The fasting performed as nafl in Shawwal does not substitute for the missed Ramadan fasting, so, it is fardh to make qada separately for the missed Ramadan fastings. As it is not valid to make inteniton for both qada and nafl for one fasting, one should make intention for only one of these while fasting in Shawwal, too. While fasting in Shawwal, if one makes intention for the qada of missed Ramadan fastings, it will be valid as a qada fasting.

Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS

What Is The Importance Of Suhoor Meal in Islam?