This ovulation calendar takes the length of your ovulation cycle into account. For example if your ovulation cycle is 28 days, (average length) than
your next ovulation will start 14 (i.e. half the length of your typical cycle) days back from the date that your next cycle is scheduled to start.
The length of your typical ovulation cycle is divided in half and rounded up to the nearest even number, (i.e. if your cycle is 31 days, we use 31 / 2 + 1 = 16).