Rak‘aat of the Daily Prayers — 51 Rak‘aat
In Shia (Ja‘fari) fiqh a full day of prayer is 51 rak‘aat: 17 obligatory (wajib) rak‘aat in the five daily prayers, and 34 recommended (nafilah / mustahab) rak‘aat prayed around them, which include the 11 rak‘aat of Namaz-e-Shab (Tahajjud). The obligatory prayers must never be missed; the nawafil are highly recommended and, according to the narrations, make up for whatever shortfall is in the obligatory ones.
The 17 Obligatory Rak‘aat
Fajr (Subh) — 2 rak‘aat
Zuhr — 4 rak‘aat
Asr — 4 rak‘aat
Maghrib — 3 rak‘aat
Isha — 4 rak‘aat
2 + 4 + 4 + 3 + 4 = 17 rak‘aat
While travelling (with the conditions of qasr) Zuhr, Asr and Isha are shortened to 2 rak‘aat each; Fajr and Maghrib stay the same, making 11 rak‘aat.
The 34 Recommended Rak‘aat (Nawafil)
Each nafilah is prayed in units of two rak‘aat, exactly like the Fajr prayer, with the niyyah of that nafilah. Witr alone is a single rak‘ah.
Nafilah of Fajr — 2 rak‘aat, before the Fajr prayer. Its time begins after Namaz-e-Shab (from the first dawn) and lasts until the redness appears in the eastern sky.
Nafilah of Zuhr — 8 rak‘aat, before the Zuhr prayer; from the beginning of Zuhr time until the shadow of a stick reaches two-sevenths (2/7) of its length.
Nafilah of Asr — 8 rak‘aat, before the Asr prayer; until the shadow reaches four-sevenths (4/7) of its length.
Nafilah of Maghrib — 4 rak‘aat, after the Maghrib prayer, until the redness in the western sky disappears.
Nafilah of Isha (Wutayrah) — 2 rak‘aat prayed sitting, after the Isha prayer, until the middle of the night. Because it is prayed sitting, it is counted as one rak‘ah.
Namaz-e-Shab (Tahajjud) — 11 rak‘aat, from the middle of the night until the Fajr adhan; detailed below.
2 + 8 + 8 + 4 + 1 + 11 = 34 rak‘aat
Namaz-e-Shab (Tahajjud) — 11 Rak‘aat
وَمِنَ الَّيْلِ فَتَهَجَّدْ بِهٖ نَافِلَةً لَّكَ عَسٰى اَنْ يَّبْعَثَكَ رَبُّكَ مَقَامًا مَّحْمُوْدًا 79
Wa minal-layli fatahajjad bihī nāfilatan lak, ʿasā an yabʿathaka Rabbuka maqāman maḥmūdā.
And keep vigil for a part of the night, as a supererogatory devotion for you. It may be that your Lord will raise you to a praiseworthy station. (Surah al-Isra, 17:79)
Namaz-e-Shab is the most emphasised of all the nawafil. Its time is from the middle of the night (halfway between sunset and the Fajr adhan) until the Fajr adhan, and the best time is the last part of the night, close to dawn. It is prayed in three parts:
Nafilah of the Night — 8 rak‘aat, prayed as four prayers of two rak‘aat each, with the niyyah “I pray two rak‘aat of Nafilah-e-Shab, qurbatan ilallah.”
Namaz-e-Shaf‘ — 2 rak‘aat, one prayer, with the niyyah of Shaf‘.
Namaz-e-Witr — 1 rak‘ah, with the niyyah of Witr. After Surah al-Hamd it is recommended to recite Surah al-Ikhlas three times, then Surah al-Falaq and Surah al-Nas, and then to raise the hands for a long qunut.
Recommended in the qunut of Witr:
Pray for forty (or more) believers, men and women, by name.
Say seventy times: اَسْتَغْفِرُ اللّٰہَ رَبِّیْ وَاَتُوْبُ اِلَیْہِ
Say seven times: هٰذَا مَقَامُ الْعَائِذِ بِكَ مِنَ النَّارِ
Say three hundred times: اَلْعَفْو
8 + 2 + 1 = 11 rak‘aat
The Full Day at a Glance
Night — Namaz-e-Shab 11 → Nafilah of Fajr 2 → Fajr 2
Midday — Nafilah of Zuhr 8 → Zuhr 4 → Nafilah of Asr 8 → Asr 4
Evening — Maghrib 3 → Nafilah of Maghrib 4 → Isha 4 → Wutayrah 2 (sitting, counted as 1)
17 obligatory + 34 recommended = 51 rak‘aat
Friday and Travel
Friday — four rak‘aat are added to the sixteen rak‘aat of the Zuhr and Asr nawafil, making twenty. It is better to pray all twenty before the sun passes the meridian (before Zuhr time).
Travel — when the prayers are shortened (qasr), the nawafil of Zuhr and Asr are dropped, and the nafilah of Isha is prayed only with the hope of reward (raja’). The nafilah of Maghrib, Namaz-e-Shab and the nafilah of Fajr remain.
All nawafil may be prayed sitting, though standing is better. There is no adhan or iqamah for them, and reciting a surah after al-Hamd is not obligatory in a nafilah. The numbers and times above follow the well-known rulings of the maraji‘; where your own marja‘ differs, follow his ruling.