Period Calculator
Calculate your next period, ovulation estimate, and fertile window.
Trying to conceive?
Discover insights about your reproductive health and get personalized guidance with our clinical assessment.
Take SORA Fertility AssessmentUnderstanding Your Menstrual Cycle & Fertile Window
Whether you are trying to conceive or simply want to understand your body better, tracking your menstrual cycle is one of the most powerful steps you can take for your reproductive health. The SORA Period Calculator uses clinical averages to estimate your next period, your likely ovulation day, and the most fertile days of your cycle.
What is the "Fertile Window"?
Your fertile window is the brief period during your menstrual cycle when pregnancy is possible. It typically spans six days: the five days leading up to ovulation, plus the day of ovulation itself. Sperm can survive in the female reproductive tract for up to 5 days, which is why having intercourse before you actually ovulate can still result in conception.
How do you calculate ovulation?
Ovulation is the release of a mature egg from the ovary. For women with a standard 28-day cycle, ovulation usually occurs around day 14. However, the true medical calculation is that ovulation happens approximately 14 days before the start of your next period.
This means if you have a 32-day cycle, you likely ovulate around day 18, not day 14. Our calculator handles this math automatically to give you the most accurate prediction possible based on your cycle length.