They request from you a [legal] ruling. Say, "Allāh gives you a ruling concerning one having neither descendants nor ascendants [as heirs]." If a man dies, leaving no child but [only] a sister, she will have half of what he left. And he inherits from her if she [dies and] has no child. But if there are two sisters [or more], they will have two thirds of what he left. If there are both brothers and sisters, the male will have the share of two females.1 Allāh makes clear to you [His law], lest you go astray. And Allāh is Knowing of all things.
Translation: Saheeh International (English)
1 This verse relates to siblings from the father's side or from both parents, whereas in Āyah 12 it concerned those from the mother's side alone.
They ask you, O Messenger, to give them a ruling with respect to the inheritance of the person who dies without any direct heirs, such as a father or child. Say: Allah explains the ruling with respect to such a person: If a person without any parent or child dies and he has a full sister or a half sister, she will receive half of the wealth he leaves – it being her set share. His full brother or half brother will receive whatever wealth he leaves behind by way of agnation, if there are no stipulated heirs; yet if there are stipulated heirs, he will inherit the balance that remains. If there are two or more full sisters or half sisters, they will inherit two thirds as their set share. If there are male and female (full or half) siblings, they will inherit by way of agnation in accordance with the rule: the male receives equivalent to the share of two females, which means that the share of the male will be double that of the female. Allah explains to you the ruling for the person who dies without direct heirs, as well as other laws of inheritance, so that you do not go astray in this regard. Allah knows everything and nothing is hidden from Him.