Short answer
Intend in your heart the specific prayer you are making up, for example "the Dhuhr I missed yesterday". If you owe many and cannot tell which day each is from, intend "the first Fajr I owe" (or the last) and repeat that each time. You do not need to say the words aloud, and a qada prayer is prayed just like the original.
For a qada (make-up) prayer the intention must name the prayer, such as Fajr or Dhuhr, and that it is a make-up. When several of the same prayer are owed, the Hanafi texts allow intending "the first Dhuhr I owe" or "the last Dhuhr I owe", which settles which one is being paid. A missed witr is made up as three rakats with qunut.
Other madhhabs
- Shafi'i
- Naming the prayer is enough; in the relied-upon view you need not intend qada explicitly or specify the day.
- Hanbali
- Naming the prayer is enough, and intending qada explicitly is not required.
Explanation
A prayer prayed in its time is called ada. A prayer prayed after its time has passed is qada, often written qaza in Urdu. A qada prayer has the same rakats and method as the original: Fajr is two, Dhuhr four, and so on, with only the fard and witr made up.
The intention (niyyah) is a decision in the heart. For one missed prayer, intend that exact prayer: "I am praying the Asr I missed today". Someone who owes months or years of prayers cannot remember the dates, so the Hanafi texts give a simple formula: intend "the first Fajr that I owe" each time. Each time you pray one, the next becomes "the first", and you work through the debt in order. Intending "the last" works the same way from the other end.
- Out loud? Not needed. Saying it softly is allowed if it helps you focus; see saying the niyyah out loud.
- Several at once: you can pray several qada prayers one after another, but each is its own prayer with its own intention. They cannot be merged into one.
- When: any time except the three times when no prayer is valid. Qada is allowed after Fajr and after Asr.
- Privately: it is better not to tell people you are making up missed prayers.
To work out how many you owe, use the qada calculator. The wider ruling is in making up years of missed prayers, and the order in do you have to make up missed prayers in order.
The evidence
Sahih al-Bukhari 1
Sahih... إنما الأعمال بالنيات ...
"Actions are only by intentions."
Every prayer, including a make-up, needs an intention.
Sahih Muslim 684
Sahih... من نسي صلاة فليصلها إذا ذكرها ...
"Whoever forgets a prayer should pray it when he remembers it."
Missed prayers are made up.
Where the ruling is recorded
- al-Durr al-Mukhtar with Radd al-Muhtar, Kitab al-Salah, chapter on make-up prayers (qada al-fawa'it). When many prayers are owed, one intends the first or last of that prayer owed.
- Nur al-Idah with Maraqi al-Falah, Chapter on make-up prayers. Qada prayers are prayed like the original, and only fard and witr are made up.
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.