Fertility Calculator

• First Day of Last Period: Select the first day of your most recent menstrual cycle.

• Cycle Length: Enter your cycle length in days if it differs from the standard 28 days. The cycle length refers to the total duration from the first day of one period to the day before the next period begins.

• Calculate: Click the "Calculate" button to estimate your ovulation day and fertile days.

• Results: 

  • Ovulation Day: The estimated day of ovulation, when an egg is released from the ovary.

  • Fertile Window: The days around ovulation when conception is most likely. This includes up to 5 days before ovulation (because sperm can survive in the female body for several days) and 1 day after ovulation (while the egg is still viable).

  • Implantation Timing: If fertilization occurs, implantation usually happens about 6–12 days after ovulation. The calculator shows this possible timeframe.

  • Next Period: If pregnancy does not occur, the expected start date of your next menstrual period.

  • Pregnancy Testing: The earliest date when a pregnancy test can reliably be taken (after your missed period).

  • Theoretical Due Date: If conception takes place, the tool estimates a due date approximately 266 days after ovulation. Most births occur within a two-week window around this date, which will also be shown.

Note: This tool is based on statistical averages and should not be used for contraception. For medical advice, always consult a healthcare professional.