This happens when the ovary releases an egg ready to be fertilized, or ovulation occurs. Intercourse in these key days increases the chances of a successful fertilization, i.e., become pregnant. How to calculate the fertile days? In principle, the day in which you ovulas is your most fertile day. Not knowing with certainty what is the day of ovulation, are considered also the days before and after the likely date in that ovularas, both to prevent and seek to become pregnant. To make the calculation we have to know with certainty what is the length of your cycle and what was the first day of our last menstruation. Your ovulation date will be around 14 days before the end of the cycle. That is why that usually assert that fertility in women BBC extends from day 12 to 16 of your menstrual cycle. It is difficult to make these calculations? For this is that there is a calculator of fertility, also called ovulation, that calculator you It will do the simple task if you’re a woman with regular cycles. Anyway you will have to take into account that this calculator is an application to determine the approximate date in that ovularas, therefore, what your peak fertility days. It is not a calculation accurate but indicative, because as everything related to the cycle, may vary with environmental and psychological conditions. Original author and source of the article