Short answer
The Prophet ﷺ said Allah has ninety-nine names, and whoever learns and keeps them enters Paradise. Most scholars say this does not limit His names to 99. It means there are 99 that carry this special reward, and Allah has other names, some of which He kept in His own knowledge.
The names of Allah are fixed by revelation (tawqifi). Belief in all of them is required, and the majority of Sunni scholars, Hanafi commentators among them, hold that the ninety-nine in the hadith are not the full count of His names.
The four schools agree on this.
Explanation
The hadith in al-Bukhari and Muslim says Allah has ninety-nine names, one hundred less one, and whoever "enumerates" them (ahsaha) enters Paradise. Scholars explain ahsaha as more than counting: it means learning them, understanding their meanings, calling on Allah by them and letting them shape your conduct.
The hadith itself does not list the names. The well-known list of 99 comes from a narration in al-Tirmidhi, and many hadith scholars say the list was added by a narrator rather than said by the Prophet ﷺ. That is why lists differ slightly from book to book. Each name on them is still found in the Quran or Sunnah.
Why do most scholars say there are more than 99? Because of a dua the Prophet ﷺ taught for times of worry, found in the Musnad of Imam Ahmad, which asks Allah by every name He has given Himself, taught to anyone, revealed in His book, or kept in the knowledge of the unseen with Him. A name kept with Allah alone cannot be among a list we know. So the 99 are a special set, not the total.
Because the names come from revelation, Muslims do not make up new ones. Pick a few names, learn their meanings and use them in your duas: "Ya Ghafur, forgive me", "Ya Razzaq, provide for me". You can study each one on our page of the 99 names of Allah.
The evidence
Quran, Surah Al-A'raaf 7:180
وَلِلَّهِ ٱلْأَسْمَآءُ ٱلْحُسْنَىٰ فَٱدْعُوهُ بِهَا ۖ وَذَرُوا۟ ٱلَّذِينَ يُلْحِدُونَ فِىٓ أَسْمَٰٓئِهِۦ ۚ سَيُجْزَوْنَ مَا كَانُوا۟ يَعْمَلُونَ ﴿١٨٠﴾
And to Allah belong the best names, so invoke Him by them. And leave [the company of] those who practice deviation concerning His names. They will be recompensed for what they have been doing.
Commands calling on Allah by His names.
Quran, Surah Al-Hashr 59:24
هُوَ ٱللَّهُ ٱلْخَٰلِقُ ٱلْبَارِئُ ٱلْمُصَوِّرُ ۖ لَهُ ٱلْأَسْمَآءُ ٱلْحُسْنَىٰ ۚ يُسَبِّحُ لَهُۥ مَا فِى ٱلسَّمَٰوَٰتِ وَٱلْأَرْضِ ۖ وَهُوَ ٱلْعَزِيزُ ٱلْحَكِيمُ ﴿٢٤﴾
He is Allah, the Creator, the Inventor, the Fashioner; to Him belong the best names. Whatever is in the heavens and earth is exalting Him. And He is the Exalted in Might, the Wise.
Lists several names and says the best names are His.
Sahih al-Bukhari 2736
Sahih... إِنَّ لِلَّهِ تِسْعَةً وَتِسْعِينَ اسْمًا مِائَةً إِلاَّ وَاحِدًا ...
"Allah has ninety-nine names, one hundred less one. Whoever learns and keeps them will enter Paradise."
The source of the number 99 and of the reward for learning them.
Where the ruling is recorded
- Sharh Sahih Muslim (al-Nawawi), Kitab al-Dhikr, chapter on the names of Allah. Reports the agreement of scholars that the hadith does not limit Allah's names to ninety-nine.
- Sharh al-Aqa'id al-Nasafiyya (al-Taftazani), Section on the names of Allah. Explains that Allah is named only by what revelation gives.
This answer is pending review by the scholars on our team. 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.