Ovulation Calculator
Calculate your fertile window and ovulation
Last Period Start Date
What is Ovulation Calculator?
The Ovulation Calculator predicts your most fertile days based on your menstrual cycle length and last period start date. It identifies your likely ovulation day and the fertile window surrounding it, helping with family planning whether you are trying to conceive or track your cycle.
How to use
- Enter the first day of your last menstrual period.
- Input your average cycle length in days (typically 21-35 days).
- View your predicted ovulation date, fertile window, and next expected period across multiple upcoming cycles.
Result
Your last period started on March 1 with a 28-day cycle. Ovulation is predicted around March 15 (day 14). Your fertile window is March 12-17, and your next period is expected around March 29.