Question
I will perform ‘Umrah and I want to shave my hair totally. If I want to perform another ‘Umrah, I may not have any hair to shave. Is this permissible? If this is not permissible, what should I do? I want to shave it because I may not be able to perform another ‘Umrah.
Answer
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.
If you intend to perform two ‘Umrahs, you can shorten your hair after the first ‘Umrah so that there would remain some hair to shorten or shave after the next ‘Umrah. This is because the obligation is fulfilled by shortening despite the fact that shaving the hair is better. The Prophet said: "‘O Allah, have mercy upon those who shave their hair.” His Companions, may Allah be pleased with them, said, “O Messenger of Allah, what about those who shorten their hair?” The Prophet said after the third time (of invoking for those who shaved their head): “And those who shorten their hair.’" [Al-Bukhari and Muslim]
If you shave your hair, you should wait until your hair grows then perform the second ‘Umrah. If you perform ‘Umrah before your hair grows, this would nonetheless be permissible.
Ibn Qudaamah said in Al-Mughni, "‘Ali, may Allah be pleased with him, said that it is permissible to perform ‘Umrah once a month." Anas, may Allah be pleased with him, would perform ‘Umrah whenever his hair grew enough to be shaved. This was narrated by Ash-Shaafi‘i, may Allahhave mercy upon him, in his Musnad. ‘Ikrimah said that one can perform ‘Umrah if he has hair that can be shaved by a razor. ‘Ataa’ said that one may perform ‘Umrah twice every month if he so wishes. Ahmad said, "If a man performs ‘Umrah, he should shave or shorten his hair, and the hair can be shaved every ten days."
And Allah knows best.