Ovulation
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Ovulation typically lands about 14 days before the next period — not 14 after the last. Enter your cycle and get the estimated day plus the six-day fertile window.
The 14 days that count backwards
The stable half of the cycle is the luteal phase — the roughly 14 days between ovulation and the next period. Cycle length varies at the front, not the back: a 32-day cycle typically ovulates around day 18, not day 14. That's the whole calculation:
Why the window is six days
Sperm survive up to about five days in fertile conditions; the egg lives roughly 12–24 hours. Conception is therefore possible from about five days before ovulation through the day itself — with the two days before ovulation the statistical peak.
The honest accuracy note
Calendar math assumes your luteal phase is 14 days and your cycles are regular — both vary between people and between months. For meaningful precision, ovulation predictor kits (LH surge), basal body temperature, or cervical-mucus tracking read your actual cycle rather than the average one; anyone with irregular cycles should lean on those or a clinician rather than a calendar. Once there's news, the due date calculator takes over.
Ovulation FAQ
Around day 14 — but the reliable rule is 14 days before the next period. On a 32-day cycle that's about day 18, which is why cycle length matters.
About six days: the five days before ovulation (sperm lifespan) plus ovulation day itself (egg lifespan ~12–24 hours). The two days before ovulation carry the highest probability.
Only as regular as your cycles — ovulation shifts month to month even in regular cycles. LH test strips, basal temperature or cervical-mucus tracking measure the real thing and are considerably more reliable.
Calendar math alone is not a reliable contraceptive method — cycle variation makes the 'safe' days unpredictable. Discuss dependable options with a healthcare provider.