Usually 28 days (20-45)
Usually 5 days (2-10)
About Ovulation
Ovulation generally occurs about 14 days before your next period starts. The fertile window typically includes the 5 days before ovulation and the day of ovulation.
Important: This prediction is based on averages. Actual cycles can vary due to stress, illness, or other factors. Do not rely on this as your only form of birth control.
Your Cycle Prediction
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Track Your Cycle
Enter the start date of your last period and your cycle length to predict your ovulation and safe days.
About Ovulation
The ovulation calculator uses the Calendar Method. It assumes ovulation occurs 14 days before the start of the next period. Sperm can survive 3-5 days, and the egg lasts 12-24 hours, defining the fertile window.
Ovulation Day = Next Period Start - 14 days
Fertile Window Start = Ovulation Day - 5 days
Fertile Window End = Ovulation Day + 1 day
Safe Days = Days outside fertile & menstrual periods
Menstrual Cycle Phases
| Phase | Duration | Description |
|---|---|---|
| Menstrual | 3-7 days | Lining shedding |
| Follicular | 7-21 days | Follicle maturation |
| Ovulation | 1 day | Egg release, peak fertility |
| Luteal | 14 days (Fixed) | Post-ovulation, progesterone rise |
