When does a girl ovulate? in comparison to her menstrual days.

~14 d before next cy: On average, a woman’s cycle normally is between 28-32 days, but some women may have shorter or longer ones. Ovulation can be calculated by starting with the day the last menstrual period (lmp) starts or by calculating 12-16 days from the next expected period. Most women ovulate anywhere between day 11 – day 21 of their cycle, counting from the first day of the lmp.