Tracking ovulation helps pinpoint your fertile window. Identifying your peak fertility days increases the probability of conception when planning a family.
Ovulation Calculator
Reviewed
ResultUpdates as you type
Estimated Ovulation Day (Cycle Day)14cycle day
Fertile Window Start (Cycle Day)cycle day9
Fertile Window End (Cycle Day)cycle day15
- Next Period Expected (Cycle Day) cycle day
- 28
- Days Until Ovulation days
- 0
Estimate your ovulation date, most fertile window, and upcoming period start dates for natural family planning.
Estimate your peak ovulation day, 6-day fertile window, and upcoming menstrual period start dates.
How to use
- Enter your average cycle length in days (typically 28 days).
- Enter the number of days since the start of your last period.
- View your estimated ovulation day and fertile window dates.
Formula
Ovulation generally occurs 14 days before the start of the next menstrual period.
Ovulation Day Formula
Ovulation Day = Cycle Length - 14 daysFertile Window Range
Fertile Window = (Ovulation Day - 5 days) to (Ovulation Day + 1 day)Frequently asked questions
When are you most fertile during your cycle?
You are most fertile during the 5 days leading up to ovulation and the day of ovulation itself.
How long does an egg survive after ovulation?
An egg lives for approximately 12 to 24 hours after being released from the ovary.