Why it exists — even the best forget
Forgetting in prayer is part of being human, and the Sharīʿah gives a gentle fix rather than demanding the whole prayer be repeated. The Prophet ﷺ himself once prayed and miscounted, and taught the remedy from his own example:
إِنَّمَا أَنَا بَشَرٌ مِثْلُكُمْ أَنْسَىٰ كَمَا تَنْسَوْنَ، فَإِذَا نَسِيتُ فَذَكِّرُونِي، وَإِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلْيَتَحَرَّ ٱلصَّوَابَ فَلْيُتِمَّ عَلَيْهِ، ثُمَّ لِيُسَلِّمْ، ثُمَّ يَسْجُدُ سَجْدَتَيْنِ
"I am a human being like you and liable to forget like you. So if I forget remind me and if anyone of you is doubtful about his prayer, he should follow what he thinks to be correct and complete his prayer accordingly and finish it and do two prostrations (of Sahu)."
ʿAbdullah ibn Masʿud (ra) — Sahih al-Bukhari 401; also Sahih Muslim, Kitab al-Masajid (site reader no. 1174)
These two prostrations are done just like the prostrations of the prayer itself — the same position, the same tasbīḥ — and they set right an unintentional slip. (Deliberately adding or dropping an obligatory part still invalidates the prayer; sujūd as-sahw is for genuine forgetfulness and uncertainty.)
The three causes — and when to prostrate
Scholars group what triggers sujūd as-sahw into three cases. The evidences also indicate when the two prostrations fall — before or after the closing salām:
Each cause has a worked example and the point at which the two prostrations are made.
Sujud as-sahw has three causes. First, addition (ziyadah): adding an extra bowing, prostration or rakah by mistake — make the two prostrations after the salam, as the Prophet did in the Dhul-Yadayn incident. Second, omission (naqs): leaving out a wajib such as the first tashahhud — make the two prostrations before the salam, as in the hadith of Ibn Buhaynah. Third, doubt (shakk): being unsure how many rakahs you prayed — build on what you are certain of (the lesser number), complete the prayer, and prostrate twice before the salam. In every case the two prostrations are performed exactly like the prayer's own prostrations.
You add something by mistake — an extra bowing, prostration, or a whole rakʿah (e.g. praying Ẓuhr as five).
→ prostrate after the salāmYou leave out a wājib — most commonly rising without the first sitting (tashahhud) and not returning to it.
→ prostrate before the salāmYou're unsure how many rakʿahs you prayed — three or four? Build on the number you are certain of (the lesser).
→ prostrate before the salāmIn every case the two prostrations are performed exactly like the prayer's own prostrations, then the salām is given.
The "after the salām" case rests on the well-known incident of Dhul-Yadayn, when the Prophet ﷺ prayed only two rakʿahs of a four-rakʿah prayer, was reminded, completed the prayer, gave salām, and then prostrated twice (Sahih al-Bukhari 1229; Sahih Muslim, Kitab al-Masajid — site reader no. 1190). The "before the salām" case for a missed first tashahhud is from the hadith of ʿAbdullah ibn Buḥaynah, when the Prophet ﷺ stood up without the first sitting and prostrated twice before the salām (Sahih al-Bukhari 1224; Sahih Muslim, Kitab al-Masajid — site reader no. 1169).
When you simply can't remember
The most common situation is losing count. The Sunnah gives a clear rule: don't guess — build on certainty (the smaller number you're sure of), complete the prayer, and prostrate:
إِذَا شَكَّ أَحَدُكُمْ فِي صَلَاتِهِ فَلَمْ يَدْرِ كَمْ صَلَّىٰ، ثَلَاثًا أَمْ أَرْبَعًا، فَلْيَطْرَحِ ٱلشَّكَّ وَلْيَبْنِ عَلَىٰ مَا ٱسْتَيْقَنَ، ثُمَّ يَسْجُدُ سَجْدَتَيْنِ قَبْلَ أَنْ يُسَلِّمَ
"When any one of you is in doubt about his prayer and he does not know how much he has prayed, three or four (rak'ahs), he should cast aside his doubt and base his prayer on what he is sure of, then perform two prostrations before giving salutations."
Abu Saʿid al-Khudri (ra) — Sahih Muslim — site reader no. 1172, Kitab al-Masajid
So if you can't decide between three and four, treat it as three (the certain amount), pray the last rakʿah, and prostrate twice before the salām. If instead your stronger impression settles on one number, some scholars (following the hadith of Ibn Masʿud) allow you to act on that stronger estimate and prostrate afterwards — but when in real doubt, the safe rule above is the one to lean on.
How to perform sujūd as-sahw
- When you reach the point for it (before the salām for omission/doubt; after the salām for addition), say Allāhu akbar and go into the first prostration — exactly like a prostration of the prayer, with its tasbīḥ (Subḥāna Rabbiyā l-Aʿlā).
- Sit up with Allāhu akbar, pause briefly (as in the sitting between the two sajdahs).
- Say Allāhu akbar and make the second prostration the same way.
- If the prostrations were before the salām: sit back up and give the salām to end the prayer. If they were after the salām: give the salām again to close.
There is no separate obligatory duʿāʾ for it, and no extra tashahhud is required in the more established view. The prayer is now complete and sound.
Do
- Build on certainty (the lesser number) when unsure
- Make two prostrations like the prayer's own
- Prostrate before salām for omission & doubt
- Prostrate after salām for an addition
- Continue calmly — a slip does not void the prayer
Avoid
- Guessing a number you're not sure of
- Restarting the whole prayer for a small slip
- Adding or dropping a pillar on purpose
- Inventing a special long duʿāʾ for the two sajdahs
- Anxiety and waswasah over every prayer
Two other prostrations — sujūd at-tilāwah and sujūd ash-shukr
Sujūd as-sahw is not the only prostration made outside the fixed positions of the prayer. The Sunnah establishes two others, and knowing them keeps the three from being confused.
Sujūd at-tilāwah — the prostration of recitation
Certain verses of the Quran are āyāt sajdah — verses of prostration. When one recites such a verse, or hears it recited, it is from the Sunnah to prostrate once. The Prophet ﷺ did so, and those with him prostrated along with him:
كَانَ النَّبِيُّ ﷺ يَقْرَأُ عَلَيْنَا السُّورَةَ فِيهَا السَّجْدَةُ، فَيَسْجُدُ وَنَسْجُدُ، حَتَّىٰ مَا يَجِدُ أَحَدُنَا مَكَانَ جَبْهَتِهِ
"Narrated Ibn `Umar:When the Prophet (ﷺ) recited a Sura that contained the prostration he would prostrate and we would do the same and some of us (because of the heavy rush) could not find a place for prostration"
ʿAbdullah ibn ʿUmar (ra) — Sahih al-Bukhari 1075
Scholars differ on its conditions. Many hold that it is a prayer-like act, so wuḍūʾ and facing the qiblah are required or at least recommended; others — including a position reported among the Companions — hold that it is not a ṣalāh in the full sense, so ṭahārah is not a condition for it. Both views are held within Ahl as-Sunnah: prostrating with wuḍūʾ and facing the qiblah is the safer and more complete practice, while those who prostrate without them upon hearing a verse of prostration have scholarly precedent for doing so.
Sujūd ash-shukr — the prostration of gratitude
When a blessing arrives or a distress is lifted — good news, a danger averted, a long-awaited relief — the Sunnah is to fall in prostration out of thanks to Allah:
كَانَ إِذَا أَتَاهُ أَمْرٌ يَسُرُّهُ، أَوْ بُشِّرَ بِهِ، خَرَّ سَاجِدًا شُكْرًا لِلَّهِ
"When anything came to the Prophet (ﷺ) which caused pleasure (or, by which he was made glad), he prostrated himself in gratitude to Allah."
Abu Bakrah (ra) — Sunan Abi Dawud 2774
Like sujūd at-tilāwah, it is a single prostration, made at the moment the blessing reaches you. Neither of these two is sujūd as-sahw: the prostration of forgetfulness is always two prostrations, tied to a slip inside the prayer — while tilāwah answers a verse, and shukr answers a blessing.
Frequently asked questions
Before the salām or after — does it really matter?
Both are valid, and the prayer is correct either way — this is a point the madhhabs differ on. The evidences above tie omission and doubt to before the salām and an addition (like Dhul-Yadayn) to after it, which is a clear and easy rule to follow. If you do it on the "wrong" side out of forgetfulness, your prayer still stands.
I forgot the first tashahhud but only remembered after standing fully — do I sit back down?
No. Once you have stood up completely, continue the prayer and make sujūd as-sahw (before the salām) at the end. If you had not yet stood fully, you return to the sitting. This is exactly the situation of Ibn Buḥaynah's hadith.
Does sujūd as-sahw fix a missed pillar (rukn), like a whole rakʿah?
A missing pillar must first be made up — e.g. if you missed a rakʿah, you pray it — and then sujūd as-sahw is added. The two prostrations mend the forgetfulness; they do not replace an omitted pillar. A deliberately omitted pillar invalidates the prayer.
What if I get constant waswasah (whispers) about my count?
Persistent, baseless doubt (waswasah) is to be ignored, not acted upon — otherwise a person would prostrate endlessly. Act only on genuine uncertainty. Seek refuge in Allah from Shayṭān, proceed on your strong sense, and do not let the whispers rule your worship.
Take the full guide with you
What to do when you slip in salah — the three causes, when to prostrate, and exactly how — with every hadith cited, in one PDF.
- Addition, omission & doubt
- Before or after the salām
- Step-by-step how-to
- A5, print-friendly, free to share
Related: How to Pray — step by step · Congregational Prayer · Sunnah & Night Prayers.
