Short answer
In the Hanafi school, missed Ramadan fasts can be made up at any time, on separate days or in a row, but you should not delay without reason. If the next Ramadan comes first, you still simply make them up, with no extra fidya. The other three schools add one fidya per day if you delayed past the next Ramadan without an excuse.
Qada of Ramadan is wajib with an extended time: it may be done at any time and the days need not be consecutive. Hastening is better, since death may come first, and anyone who dies owing fasts should leave a wasiyyah (bequest) for fidya. Delaying past the next Ramadan requires no fidya. Qada may not be done on the two Eid days or the three days after Eid al-Adha.
Other madhhabs
- Shafi'i
- Qada must be done before the next Ramadan; delaying it past then without an excuse requires one mudd of food per day as well as the qada.
- Maliki
- Delaying qada past the next Ramadan without an excuse requires fidya for each day as well as the qada.
- Hanbali
- Delaying qada past the next Ramadan without an excuse requires fidya for each day as well as the qada.
Explanation
The Quran says the sick person and the traveller make up an equal number of other days, and sets no deadline. Aisha said she would sometimes owe fasts from Ramadan and could only make them up in Shaban, because of her duties to the Prophet ﷺ. The scholars take from this that qada may be delayed, and the other schools take Shaban as the latest point.
- Separate days are fine. You do not need to fast them in a row.
- Intention at night. Make the intention before fajr and specify that it is a qada fast.
- Forbidden days. Do not fast on Eid al-Fitr, Eid al-Adha or the three days after it.
- Not sure how many? Make up the number you are reasonably sure of, leaning towards more.
Even though the Hanafi school allows delay, life is uncertain. Try to finish your qada before the next Ramadan, which also keeps you clear of the difference with the other schools. If many years of fasts are owed, fast steadily, for example on Mondays and Thursdays.
Use the qada calculator to count what you owe. If you can never make the fasts up, see what is fidya. To combine with Shawwal fasts, see qada and Shawwal.
The evidence
Quran, Surah Al-Baqara 2:184
أَيَّامًۭا مَّعْدُودَٰتٍۢ ۚ فَمَن كَانَ مِنكُم مَّرِيضًا أَوْ عَلَىٰ سَفَرٍۢ فَعِدَّةٌۭ مِّنْ أَيَّامٍ أُخَرَ ۚ وَعَلَى ٱلَّذِينَ يُطِيقُونَهُۥ فِدْيَةٌۭ طَعَامُ مِسْكِينٍۢ ۖ فَمَن تَطَوَّعَ خَيْرًۭا فَهُوَ خَيْرٌۭ لَّهُۥ ۚ وَأَن تَصُومُوا۟ خَيْرٌۭ لَّكُمْ ۖ إِن كُنتُمْ تَعْلَمُونَ ﴿١٨٤﴾
[Fasting for] a limited number of days. So whoever among you is ill or on a journey [during them] - then an equal number of days [are to be made up]. And upon those who are able [to fast, but with hardship] - a ransom [as substitute] of feeding a poor person [each day]. And whoever volunteers excess - it is better for him. But to fast is best for you, if you only knew.
Missed days are made up, with no deadline stated.
Sahih al-Bukhari 1950
Sahih... كان يكون علي الصوم من رمضان فما أستطيع أن أقضي إلا في شعبان ...
"Aisha said: I would owe fasts from Ramadan and could not make them up except in Shaban."
Qada can be delayed and does not have to follow Ramadan straight away.
Where the ruling is recorded
- al-Hidaya, Kitab al-Sawm, chapter on what requires qada and kaffarah. The days may be made up separately or consecutively, and delaying past the next Ramadan requires no fidya.
- Bada'i al-Sana'i, Kitab al-Sawm, section on qada. Qada of Ramadan is wajib with an extended time.
- al-Majmu' (Nawawi), Kitab al-Siyam. The Shafi'i view of fidya for delay past the next Ramadan.
This answer is pending review by the scholars on our team. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.