Free Ovulation Calculator
Estimate your ovulation day and fertile window based on your menstrual cycle length.
days
Estimated Ovulation Day
14 day of cycle
Fertile Window Start12 day of cycle
Fertile Window End15 day of cycle
Fertile Window Length4 days
Estimated Ovulation Day vs Cycle Length
Ovulation Estimation
Ovulation Day = Cycle Length - 14
The luteal phase (post-ovulation) is typically 14 days. The fertile window spans from 2 days before ovulation to 1 day after.
Fertile Window
Sperm can survive up to 5 days, but the most fertile period is the 2-3 days before and the day of ovulation.
Example Calculation
A woman with a 28-day cycle.
- 01Ovulation day = 28 - 14 = day 14
- 02Fertile window start = 14 - 2 = day 12
- 03Fertile window end = 14 + 1 = day 15
- 04Fertile window = days 12-15 (4 days)
Frequently Asked Questions
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