Ovulation Calculator
Identify your most fertile days to maximize your chances of conception.
The Biological Calculation
This calculation assumes a luteal phase (time after ovulation) of 14 days, which is standard for most women regardless of cycle length.
Ovulation Date = Next Period Date - 14 Days
Next PeriodCalculated as LMP + Cycle Length
Fertile Window5 days prior to Ovulation + Ovulation Day
Understanding Your Menstrual Cycle
A typical menstrual cycle is often described as 28 days long, but healthy cycles can range from 21 to 35 days.
Follicular Phase
Starts on day 1 of your period. The body produces hormones to mature eggs in the ovaries.
Ovulation
Around day 14 (in a 28-day cycle), a mature egg is released. This is peak fertility.
Frequently Asked Questions
When is my most fertile window?
Your fertile window includes the 5 days before ovulation and the day of ovulation itself. This is when conception is most likely to occur.
Can I get pregnant outside my fertile window?
It is highly unlikely. An egg lives for only 12-24 hours after ovulation. Ideally, sperm must already be present (waiting) in the reproductive tract when ovulation occurs.
What if my cycles are irregular?
If your cycles vary by more than a few days each month, calculations based on averages may be less accurate. Tracking physical signs like basal body temperature (BBT) and cervical mucus is recommended.