What is Qada'?

Qada' means to perform or to pay. When you leave a prayer intentionally or unintentionally, it is a must(WAJIB)that you qada' the prayer outside of its period. Not performing the prayer is a sin.

Those who leave a prayer either because they forgot, asleep or in purpose must repent to Allah S.W.T and promise to oneself not to do it again. When do we qada' our prayer? Those must qada' when they remember as it crossed their mind. It is best to perform qada' prayer before or after the period.

Rasulullah SAW: "Sebenarnya bukanlah termasuk lalai kerana tertidur. Kelalaian itu ialah di waktu bangun. Maka apabila seseorang lupa solat atau ia tertidur, hendaklah ia melakukannya jika telah ingat atau sedar".

Abu Hanifah, Malik dan Syafei believes that it is harus to perform qada' after the period of that prayer. 

Regulations Concerning Missed Prayers

1. It is a great sin to miss a prayer without a genuine reason or real necessity and the Hadith contain great warnings about it. If a person misses a prayer due to carelessness or forgetfulness, he should repent for it sincerely and pledge before Allah not to let this happen in the future.
2. If due to a genuine reason or necessity, a prayer is missed, one should try to offer it as soon as possible (the sooner the better) and avoid delaying it unnecessarily. This is a debt which one must pay off at the first available opportunity. For one does not know when suddenly one will have to pass away into Allah's presence and present before Him one's life account.
3. If a group of people together missed a prayer, for instance, due to a collective journey where they could not offer it duly in time; or an accident taking place on a locality; or their being overpowered by sleep; they should offer the missed prayer in congregation, with audible or inaudible recitation as the case may be.
4. If an individual misses a prayer, he should offer it secretly at home, for it is sinful to miss a prayer on account of carelessness or negligence and then to offer it publicly. One may, however, offer a missed prayer in the mosque as well, but should do so quietly.
5. There is no fixed time for offering a missed prayer. One may offer it in one's own time, but the sooner the better, avoiding, however, the forbidden times.
6. If a person has missed more than one prayer, he should offer them at the first available opportunity, if possible altogether one after the other. For it is not necessary to offer a missed Zuhr prayer at the Zuhr time and a missed Asr prayer at the Asr time only.
7. If a negligent person has not offered his prayers for a long time and has missed them over months and years and then repents before Allah, he will have to offer also Prayers missed by him, because Allah might forgive him the sin of negligence, but not the prayers which he has to offer as missed Prayers in any case.
8. If a person has missed Prayers over months and years, he should determine their number, and then should start offering them accordingly, naming the prayer missed and its number, in the intention until he observes all the missed Prayers.
9. The prayers missed during a journey have to be shortened, as prescribed, if offered during the stay at a place, and the prayers missed during a stay have to be offered in full, if offered during a journey. For instance, the Zuhr, Asr and Isha Prayers, if missed during a stay, have to be offered in full (four rak'ahs each) if offered during a journey.
10. If only the Witr prayer has been missed, it has to be offered before Fajr prayer next morning. If a person has offered the Fajr prayer without first offering the missed Witr prayer, he will have to offer the Witr prayer and repeat the Fajr prayer.
11. If a patient who could offer his prayers by making symbolic signs during the illness, has missed some of them, he should make a Will to the effect that after his death his heirs should pay off compensation for the missed prayers out of one-third of his property. The compensation for one missed prayer being 1 ¼ seers of wheat, or 2 ½ seers of barley, or the price. ('Ilm al-Fiqh, Vol. II p. 126)
12. If a sick person is too weak to offer his prayers even by making symbolic signs, or remains unconscious for a period in which six consecutive prayers can be offered, he does not have to offer the missed prayers. However if he regained consciousness after missing five prayers and is in full consciousness at the time of the sixth prayer, he has to offer the five missed prayers.
13. The person who due to negligence has missed prayers over a long period of his life, and is granted later in life a sense of his religious obligations by Allah, should first of all attend to making up for the loss of the missed prayers. An easy way is this: instead of offering the Sunnat and Nafl prayers at the prescribed times, he should offer the missed Fard prayers and continue doing so till he is sure that he has offered all the missed prayers. It is unwise to offer the Sunnat and Nafl prayers regularly, besides the Fard prayers at the prescribed times, but remained wholly unmindful of so many missed prayers. Indeed, this is a debt which one must pay off without allowing the least negligence. However if a person is able to offer full prayers at the prescribed times, including the Sunnat and Nafl prayers, and offers the missed prayers as well, he may have to hope that Allah Almighty will reward him for his devotion and sincerity.
14. The Friday prayer, if missed, cannot be offered later. One may however, offer four rak'ahs of the Zuhr prayer later instead of the Friday prayer which one has missed.