Does Making Up Missed Fasts Have to Be Done Consecutively?

The Imams agreed that in order to make up missed Ramadan fasts , one must fast a number of days equal to the number of days when you did not fast, because Allah says (interpretation of the meaning): 

“…and whoever is ill or on a journey, the same number [of days which one did not observe fasts must be made up] from other days.” [Al-Baqarah 2:185]

It is not essential that these days be consecutive; you may fast them one after the other, or you may fast them separately, whether you fast one day each week or each month, or whatever is easy for you.

The evidence for that is the verse quoted above, because it does not specify that the days fasted to make up missed Ramadan fasts should be consecutive , rather it only stipulates that the number of days fasted be equal to the number of days missed. (See Al-Majmu`, 6/167; Al-Mughni, 4/408) 

The Standing Committee was asked: is it permissible to make up missed Ramadan fasts on separate days? 

They replied: “Yes, it is permissible to make up missed fasts on separate days, because Allah says (interpretation of the meaning): 

“…and whoever is ill or on a journey, the same number [of days which one did not observe fasts must be made up] from other days.” [Al-Baqarah 2:185]

And Allah did not stipulate that these days must be consecutive.” (Fatawa Al-Lajnah Ad-Da’imah, 10/346) 

In Fatawa Ash-Shaykh Ibn Baz (15/352) it says: “If a person did not fast for two or three or more days, he must make up those fasts but they do not have to be on consecutive days. If he does that, it is better, but if he does not there is nothing wrong with that.” 

And Allah knows best.