Short answer
His greatest miracle is the Quran. Allah also gave him many physical miracles reported in authentic hadith: the splitting of the moon, water flowing from between his fingers, a small meal feeding a whole army, a palm trunk weeping for him, and the Night Journey to Jerusalem and the heavens.
Sunni scholars hold that the Prophet ﷺ was given both a lasting miracle, the Quran, and many sensory miracles witnessed by Companions, some reported by so many narrators that they are certain. These are signs from Allah, not powers of his own.
The four schools agree on this.
Explanation
The Prophet ﷺ said every prophet was given signs that led people to believe, and what he was given was revelation from Allah, so he hoped to have the most followers on the Day of Judgement. The Quran challenges anyone to produce even one surah like it. Its language, guidance and preservation remain a living miracle that anyone can examine today.
Companions also saw physical miracles. Some well-known ones, all in Sahih al-Bukhari or Muslim:
- The splitting of the moon in Makkah, which the Quran mentions (54:1). See Did the Prophet split the moon?
- Water from his fingers. At al-Zawra in Madinah, he put his hand in a small vessel and water flowed from between his fingers until the people, around three hundred, made wudu.
- The weeping trunk. He used to lean on a palm trunk to give the sermon. When a pulpit was made, the trunk cried out like a child until he came down and held it.
- Food multiplied. During the Trench, Jabir prepared a small meal and it fed the whole army.
- The Isra and Mi'raj, his journey to Jerusalem and the heavens in one night.
Muslims believe miracles come from Allah to confirm His messengers. They are not magic or tricks, and the Prophet ﷺ never used them for show. See Do Muslims believe in miracles? and Isra and Miraj.
The evidence
Quran, Surah Al-Qamar 54:1
بِسْمِ ٱللَّهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ ٱقْتَرَبَتِ ٱلسَّاعَةُ وَٱنشَقَّ ٱلْقَمَرُ ﴿١﴾
The Hour has come near, and the moon has split [in two].
The splitting of the moon.
Quran, Surah Al-Israa 17:88
قُل لَّئِنِ ٱجْتَمَعَتِ ٱلْإِنسُ وَٱلْجِنُّ عَلَىٰٓ أَن يَأْتُوا۟ بِمِثْلِ هَٰذَا ٱلْقُرْءَانِ لَا يَأْتُونَ بِمِثْلِهِۦ وَلَوْ كَانَ بَعْضُهُمْ لِبَعْضٍۢ ظَهِيرًۭا ﴿٨٨﴾
Say, "If mankind and the jinn gathered in order to produce the like of this Qur'an, they could not produce the like of it, even if they were to each other assistants."
The Quran's challenge, his lasting miracle.
Sahih al-Bukhari 4981
Sahih... وإنما كان الذي أوتيت وحيا أوحاه الله إلي ...
"What I was given is revelation that Allah revealed to me."
The Quran is his greatest miracle.
Sahih al-Bukhari 3572
Sahih... فوضع يده في الإناء ...
"He placed his hand in the vessel."
Water flowing from between his fingers.
Sahih al-Bukhari 3584
Sahih... فصاحت النخلة صياح الصبي ...
"The palm trunk cried out like a child."
The weeping trunk.
Where the ruling is recorded
- al-Shifa (Qadi Iyad), Part on his miracles. The classical collection of his miracles and their chains.
- al-Bidaya wa al-Nihaya (Ibn Kathir), Section on the proofs of prophethood (dala'il al-nubuwwa). Ibn Kathir's long list of his miracles.
- Fath al-Bari (Ibn Hajar), Commentary on Kitab al-Manaqib, chapter on the signs of prophethood in Islam. Commentary on the hadith of the water, food and trunk.
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.