Ovulation
calculator
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.
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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.