Short answer
The recitation is aloud in Fajr, the first two rakats of Maghrib and Isha, Jummah, the Eid prayers, and taraweeh and witr in Ramadan. It is silent in Dhuhr and Asr and in the third and fourth rakats of any prayer. In the Hanafi school this is wajib for the imam, so a mistake calls for sajdah sahw.
The imam must recite aloud in the loud prayers and silently in the silent ones; this is wajib. Someone praying alone may recite aloud or silently in Fajr, Maghrib and Isha, aloud being better, but must be silent in Dhuhr and Asr. Silent recitation still means moving the tongue and lips to pronounce the words, not just reading in your mind.
Other madhhabs
- Shafi'i
- The same prayers are loud and silent, but this is a sunnah, so a mistake does not call for sajdah sahw.
- Maliki
- The same prayers; loud and silent recitation are sunnah, and an error is made up with sajdah sahw.
- Hanbali
- The same prayers; it is a sunnah, and sajdah sahw for an error is allowed but not required.
Explanation
The four schools agree on which prayers are loud. The Companions learned it from hearing the Prophet ﷺ: Abu Hurayrah said that what he let them hear, they let others hear, and what he kept quiet, they kept quiet. In Dhuhr and Asr the Companions knew he was reciting only from the movement of his beard.
- Fajr: aloud in both rakats.
- Dhuhr: silent.
- Asr: silent.
- Maghrib: aloud in the first two rakats, silent in the third.
- Isha: aloud in the first two, silent in the last two.
- Jummah and the two Eids: aloud.
- Taraweeh, and witr in Ramadan when prayed with the imam: aloud.
- Sunnah and nafl prayers by day: silent. At night you may choose.
What "silent" means: the Hanafi school requires you to pronounce the words with your tongue, at least so that the letters are formed; reading only in your heart is not recitation. See praying in your head. "Loud" for someone alone means at least audible to himself and the person next to him; there is no need to shout.
Mistakes: if the imam recites aloud in a silent prayer, or silently in a loud one, for the length of a short verse or more by mistake, sajdah sahw is due. Making up a missed loud prayer: the imam of a qada congregation recites aloud; alone you have the choice. Women recite quietly in every prayer; see can a woman recite out loud in salah.
The evidence
Quran, Surah Al-Israa 17:110
قُلِ ٱدْعُوا۟ ٱللَّهَ أَوِ ٱدْعُوا۟ ٱلرَّحْمَٰنَ ۖ أَيًّۭا مَّا تَدْعُوا۟ فَلَهُ ٱلْأَسْمَآءُ ٱلْحُسْنَىٰ ۚ وَلَا تَجْهَرْ بِصَلَاتِكَ وَلَا تُخَافِتْ بِهَا وَٱبْتَغِ بَيْنَ ذَٰلِكَ سَبِيلًۭا ﴿١١٠﴾
Say, "Call upon Allah or call upon the Most Merciful. Whichever [name] you call - to Him belong the best names." And do not recite [too] loudly in your prayer or [too] quietly but seek between that an [intermediate] way.
Recitation in prayer should be measured, neither shouted nor inaudible.
Sahih al-Bukhari 772
Sahih... فما أسمعنا رسول الله صلى الله عليه وسلم أسمعناكم وما أخفى عنا أخفينا عنكم ...
"What the Messenger of Allah ﷺ let us hear, we let you hear, and what he kept from us, we keep from you."
Loud and silent recitation was learned from the Prophet's ﷺ practice.
Sahih al-Bukhari 746
Sahih... بم كنتم تعرفون ذاك قال باضطراب لحيته ...
"We asked: how did you know he recited in Dhuhr and Asr? He said: by the movement of his beard."
Dhuhr and Asr were recited silently.
Where the ruling is recorded
- al-Hidaya, Kitab al-Salah, chapter on the description of the prayer. The imam recites aloud in Fajr and the first two of Maghrib and Isha, silently in Dhuhr and Asr; the one alone has a choice in the loud prayers.
- Nur al-Idah with Maraqi al-Falah, Chapter on the wajibs of the prayer and on sajdah sahw. Loud and silent recitation in their places is wajib; sahw is due for reversing them by mistake.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. 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.