Answered by Shaykh Hamza Karamali, SunniPath Academy Teacher
Does it invalidate a woman’s prayer if she recites loudly? Does it matter if other men are present?
In the Name of Allah, Most Merciful and Compassionate
It does not invalidate a woman’s prayer if she recites out loud. Depending on the situation, however, it may or may not be sunna for her to do so. The general rule is that when a woman is praying in the presence of a non-mahram man, it is recommended for her to recite quietly. If she is praying alone or in the presence of a man who is her close relative (mahram), she takes the same ruling as a man: it is recommended for her to recite loudly wherever it is recommended for men to recite loudly and it is recommended for her to recite quietly wherever it is recommended for men to recite quietly. When she recites aloud, however, she should keep her volume lower than that of a man. (Fath al-‘Allam, 2.307)
Note : Reciting “quietly” means reciting such that one can hear oneself. Simply moving one’s lips or reciting in one’s heart does not fulfill the requirement of reciting during the prayer and if one did that, one’s prayer would be invalid.
And Allah knows best.
Hamza Karamali