Ovulation Calculator
Calculate your estimated ovulation date and 6-day fertile window based on your last period and cycle length. Includes predictions for the next 3 cycles.
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Frequently Asked Questions
How is ovulation day estimated?
Ovulation typically occurs 14 days before the next period. Add (cycle length − 14) days to your last period start date. For a 28-day cycle this is Day 14; for a 32-day cycle it is Day 18. The fertile window spans approximately 5 days before ovulation through 1 day after.
What are physical signs of ovulation?
Common signs include clear egg-white cervical mucus; a slight rise in basal body temperature (0.2–0.5°C); mild one-sided pelvic pain (mittelschmerz); positive ovulation predictor kit (OPK) indicating an LH surge; and increased libido.
Can irregular cycles affect ovulation timing?
Yes. Irregular cycles caused by stress, PCOS, or thyroid issues make calendar-based estimates unreliable. For irregular cycles, tracking basal body temperature and using OPK test strips gives a more accurate fertile window.