Short answer
Shaving the whole head is allowed for men at any time, and it is the Sunnah at the end of Hajj and Umrah. Outside those, the Prophet ﷺ usually kept his hair, so keeping hair is his normal practice, while shaving is also fine; some Hanafi scholars, including al-Tahawi, preferred shaving.
Shaving the head is permissible (mubah) for men. Keeping the hair in the manner of the Prophet ﷺ is a sunnah of habit, and shaving after Hajj and Umrah is a rite. Women may not shave their heads without a need.
The four schools agree on this.
Explanation
The Prophet ﷺ usually wore his hair to his earlobes or his shoulders, and that is the normal Sunnah style; see is long hair sunnah for men. At the end of Hajj and Umrah he shaved, and he prayed more than once for mercy on those who shave before he included those who shorten. So shaving is never something blameworthy for a man.
Outside Hajj, the Prophet ﷺ called a barber to shave the heads of the young sons of Ja'far after their father was martyred. And when he saw a boy with part of his head shaved, he said to shave all of it or leave all of it, which treats a fully shaved head as a normal option. Al-Tahawi, the great Hanafi hadith scholar, went further and regarded shaving as preferable, which shows the matter is wide.
- Allowed: a clean shave, a buzz cut, or a skin fade where the whole head is cut.
- Avoid: shaving part of the head and leaving the rest long (qaza'); see haram haircuts.
- Women: may not shave the head without a need such as illness; see can women cut their hair short.
For the rite in pilgrimage, see do you have to shave your head for umrah. For care of the hair you keep, see the Sunnah of hair care.
The evidence
Sunan Abi Dawud 4192
Grading to be checked... ادعوا لي الحلاق ...
"Call the barber for me."
The Prophet ﷺ had the heads of Ja'far's sons shaved, outside Hajj.
Sahih al-Bukhari 1727
Sahih... اللهم ارحم المحلقين ...
"O Allah, have mercy on those who shave their heads."
His dua for those who shave at the end of the pilgrimage.
Sunan Abi Dawud 4195
Graded sahih... احلقوه كله أو اتركوه كله ...
"Shave all of it or leave all of it."
A fully shaved head is a normal option; a partly shaved one is not.
Where the ruling is recorded
- Sharh Ma'ani al-Athar (al-Tahawi), Kitab al-Karahiyya, chapter on shaving the hair. Al-Tahawi's view that shaving the head is a sunnah and better than shortening.
- al-Fatawa al-Hindiyya, Kitab al-Karahiyya, chapter on circumcision, hair and nails. On shaving the head for men and the ruling for women.
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.