Find your ovulation date and 6-day fertile window based on your cycle. The calculator shows your most fertile days for the next 3 cycles.
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The first day of bleeding of your most recent period.
Count from day 1 of one period to day 1 of the next. Average is 28 days.
Usually 14 days. If you track your cycle with an app, you may know your actual luteal phase.
The luteal phase (after ovulation until next period) is usually 12–16 days, most commonly 14. Sperm can survive 5 days in the reproductive tract, so the fertile window starts 5 days before ovulation.
The 6 days ending on ovulation day — 5 days before ovulation plus the day of ovulation itself. The egg survives only 12–24 hours, but sperm can survive up to 5 days.
It is an estimate based on average cycle patterns. Actual ovulation can vary by several days depending on stress, illness, and hormonal changes. OPK tests or temperature tracking are more accurate.
The second half of the menstrual cycle — from ovulation to the next period. It is typically 12–16 days and is more consistent than the first half of the cycle.
It is very unlikely but not impossible. Sperm and eggs have unpredictable lifespans. The fertile window covers the vast majority of conception opportunities.
Ovulation typically occurs 14 days before the next period, not 14 days after the period starts. For a 28-day cycle: ovulation around day 14. For a 32-day cycle: around day 18. The fertile window is 5 days before ovulation to 1 day after.