How long after your period you can get pregnant?

How long after your period before your fertile depends entirely on your menstrual cycle. During the typical 28 day cycle a woman will ovulate around day 14 and thus be fertile between days 7-16 (up to a week beforehand when fertile cervical mucus is present that can allow the sperm to survive in the vagina for up to a week, and up to 48 hours from ovulation). Unless a woman uses Fertility Awareness Methods she cannot know when she is fertile, so you should assume you're always fertile and use contraception in order to avoid unintended pregnancy.