Praise be to Allah.
The regular Sunnah prayers are twelve rak‘ahs, for which it is narrated that whoever persists in praying them regularly, a house will be built for him in Paradise. This has been explained in the answer to question no. 1048. They are two rak‘ahs before Fajr, four rak‘ahs before Zuhr, two rak‘ahs after Zuhr, two rak‘ahs after Maghrib and two rak‘ahs after ‘Isha’.
The time for the regular Sunnah prayers that come before the obligatory prayer begins when the time for the obligatory prayer begins. So when the adhaan is given for Fajr, Zuhr or ‘Asr, then the time for the regular Sunnah prayer has also begun. Then when one has finished the obligatory prayer, the time for the regular Sunnah prayer that comes after the obligatory prayer begins, and its time lasts until the time for that prayer ends.
It says in ar-Rawd al-Murbi‘: The time for the Sunnah prayer that comes before any obligatory prayer begins when the time for that prayer begins, until the obligatory prayer has been offered, and the time for the Sunnah prayer that comes after the obligatory prayer lasts from after one has done it until the time for the obligatory prayer ends. End quote.
The Muslim should not be careless with regard to offering the regular Sunnah prayers, or delay them from the appropriate time, unless he has an excuse, such as if he forgot or is sick or is distracted with something that cannot be avoided, because this will cause him to miss out on the great reward that is bestowed upon the one who regularly offers these Sunnah prayers.
If a person does miss out on the regular Sunnah prayers, then it depends. If that was because of an excuse such as falling asleep, forgetting or being too busy, then it is permissible for him to make them up at whatever time he wants. For more information, please see the answers to questions no. 146713 and 114233.
But if he did not have an excuse, then it is not prescribed to make them up, because if an act of worship is connected to a specific time, once that time is over it cannot be made up.
al-Hajjaawi (may Allah have mercy on him) said in Zaad al-Mustaqni‘: If a person misses any of them (the regular Sunnah prayers), it is Sunnah for him to make them up.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: That is, if he misses any of these regular Sunnah prayers, it is Sunnah for him to make them up, on condition that he had a valid excuse for missing them.
The evidence for that is what is proven in the hadith of Abu Hurayrah and Abu Qataadah, about the story of how the Prophet (blessings and peace of Allah be upon him) and his Companions slept whilst travelling and missed Fajr. The Prophet (blessings and peace of Allah be upon him) prayed the regular Sunnah of Fajr first, then the obligatory prayer.
There is also the hadith of Umm Salamah, according to which the Prophet (blessings and peace of Allah be upon him) was distracted from praying the two rak‘ahs after Zuhr, then he made them up after ‘Asr. This has to do with making up the regular Sunnah prayers.
Moreover, there is the general meaning of the words of the Prophet (blessings and peace of Allah be upon him): “Whoever sleeps and misses a prayer, or forgets it, let him offer it as soon as he remembers it.” This includes both obligatory and naafil prayers, and applies if a person missed it for a valid reason, such as forgetting, falling asleep or being distracted by something that is more important. But if he missed it deliberately, until the time for it ended, then he cannot make it up, and even if he did make it up, it would not be valid as a regular Sunnah prayer per se, because the regular Sunnah prayers are acts of worship that are connected to particular times, and if a person deliberately performs acts of worship that are connected to particular times after the time for them is over, they will not be accepted from him.
The evidence for that is the hadith in which the Prophet (blessings and peace of Allah be upon him) said: “Whoever does an action that is not in accordance with this matter of ours, it will be rejected.” If a person deliberately delays an act of worship that is connected to a particular time until the time for it has ended, then he has done an action that is not in accordance with the command of Allah and His Messenger, because Allah and His Messenger have enjoined that prayers should be offered at particular times, so it will not be acceptable in this case. Moreover, just as it is not valid if done before its time, it is also not valid if it is done after its time, because there is no real difference between doing it before its time has begun or doing it after its time has ended, if that is done without a valid excuse.
The words: “Whoever misses any of them, it is Sunnah for him to make it up” are only applicable in cases where the prayer was missed for a valid excuse, because the phrase “Whoever misses any of them” implies that, because missing something implies not being able to do it. The author did not say “whoever does not do any of them”; he said “whoever misses any of them.” That is similar to when the fuqaha’ said that whoever misses the standing in ‘Arafat has missed Hajj.
End quote from ash-Sharh al-Mumti‘ (4/72). See also: Majmoo‘ Fataawa wa Rasaa’il ash-Shaykh Ibn ‘Uthaymeen (14/284)
If you missed the time for a regular Sunnah prayer for a valid excuse, then you can make it up either during the night or the following day, although hastening to make it up is preferable, and that should be done two by two. So first of all you should have the intention to pray the two rak‘ahs that come before Fajr, then the rak‘ahs that come before Zuhr, then the rak‘ahs that come after Zuhr, and so on. It is not essential to do them in order; in fact if you pray the Sunnah prayer of Maghrib or Zuhr first, it does not matter.
And Allah knows best.