The Fertile Window is shown from cycle 2 onwards if you received confirmed ovulation in the previous cycle. The Fertile Window is shown on your graph as a green-shaded area, with the predicted day of ovulation shaded with a blue vertical line. This window is the eight days when you are most likely to be able to conceive, from five days before ovulation until two days after ovulation. The window is based on the day of ovulation from the previous cycle, so if your cycles vary in length it will be less useful to you.