Q: If a woman has the means to perform Hajj but does not have a mahram to accompany her, will Hajj be compulsory upon her?
From: Ihyaaud Deen. This entry is part 4 of 7 in the series Hajj Masaail
A: It will not be compulsory upon her to go for Hajj. She should perform her Hajj when she has a mahram. However it is necessary for her to make a bequest that if she passes away without performing Hajj then Hajj-e-badl should be done on her behalf from one-third of her wealth. (Fatawa Raheemiyah 8:53)