About the Ovulation Calculator
This Ovulation Calculator estimates your next ovulation date and your fertile window. Enter basic cycle details and you receive predicted dates for ovulation, peak fertility, and the days with the highest chance of conception.
The tool follows the standard calendar method: it counts back about 14 days from the start of your next expected period, since the luteal phase typically lasts that long. You provide the first day of your last menstrual period and your average cycle length, usually between 21 and 35 days. The calculator then builds a fertile window of roughly six days, covering the five days before ovulation plus the ovulation day itself. For better accuracy, average your cycle lengths over the last three to six months before entering them. Consider a healthcare professional for personal family planning decisions.
- Enter the first day of your most recent period.
- Type your average cycle length in days.
- Press calculate and read your ovulation date and fertile window.