Short answer
Sleeping before Isha once its time has come is makruh, because the Prophet ﷺ disliked it, unless you are sure someone will wake you. Sleeping between Fajr and sunrise is disliked by many early scholars as it misses the blessed morning. The popular claim that sleeping after Asr causes madness comes from a weak report.
Sleeping after the time of Isha has entered and before praying it is makruh, and if it leads to missing the prayer it is sinful. Sleeping after Fajr until sunrise is makruh tanzihi. There is no authentic prohibition on sleeping after Asr.
The four schools agree on this.
Explanation
Abu Barzah reported that the Prophet ﷺ disliked sleeping before Isha and talking after it. The Hanafi texts record this: sleeping before Isha is makruh. The reason is clear: a person who falls asleep tired in the evening easily misses Isha altogether. If you have a reliable alarm or someone who will wake you, scholars ease the dislike, but praying first is better.
The time after Fajr is precious. The Prophet ﷺ made dua: O Allah, bless my ummah in their early mornings. Many of the early Muslims disliked sleeping between Fajr and sunrise, preferring to sit in dhikr, read Quran or start work. This is a dislike, not a sin. Shift workers, the sick and anyone who was up at night may rest after Fajr.
You may have heard that whoever sleeps after Asr and loses his mind has only himself to blame. Hadith scholars graded that report very weak or fabricated, so no ruling is built on it. A short rest in the late afternoon is permitted, as long as Maghrib is not missed.
Other sleep matters:
- Sleeping through a prayer time: if you fell asleep before the time came in and did not wake, there is no sin; pray as soon as you wake. If you slept after the time came in, knowing you would miss it, that is sinful.
- Staying up late after Isha in idle talk or scrolling is disliked, since it costs Fajr.
- Midday nap is a sunnah. See is it sunnah to nap.
The four schools broadly agree on these dislikes. See also when does Isha start and end and the qada calculator for missed prayers.
The evidence
Quran, Surah Ar-Room 30:23
وَمِنْ ءَايَٰتِهِۦ مَنَامُكُم بِٱلَّيْلِ وَٱلنَّهَارِ وَٱبْتِغَآؤُكُم مِّن فَضْلِهِۦٓ ۚ إِنَّ فِى ذَٰلِكَ لَءَايَٰتٍۢ لِّقَوْمٍۢ يَسْمَعُونَ ﴿٢٣﴾
And of His signs is your sleep by night and day and your seeking of His bounty. Indeed in that are signs for a people who listen.
Sleep by night and day is a sign of Allah, to be balanced with worship and work.
Sahih al-Bukhari 568
Sahih... كان يكره النوم قبلها والحديث بعدها ...
"He disliked sleeping before Isha and talking after it."
The basis for sleeping before Isha being makruh.
Sunan Abi Dawud 2606
Grading to be checked... اللهم بارك لأمتي في بكورها ...
"O Allah, bless my ummah in their early mornings."
The time after Fajr is blessed, so sleeping through it is disliked.
Where the ruling is recorded
- al-Durr al-Mukhtar, Kitab al-Salah, section on prayer times. Sleeping before Isha and talking after it are disliked.
- Radd al-Muhtar (Ibn Abidin), Kitab al-Salah, section on prayer times. The dislike of sleeping before Isha eases if someone will wake the sleeper.
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.