Ovulation Calculator

Frequently Asked Questions

• When do I ovulate?

  Typically ~14 days before your next period. For a 28-day cycle, that's day 14. For a 32-day cycle, day 18. Cycle length varies — luteal phase is most consistent at ~14 days.

• How long is the fertile window?

  About 6 days: the 5 days before ovulation plus the day of ovulation. Sperm survive up to 5 days; an egg lives ~24 hours.

• Can I get pregnant outside the fertile window?

  Probability is very low but not zero, due to natural variation in cycle timing. The calculator gives the highest-probability window, not a guarantee or contraceptive.

• How accurate is calendar-based prediction?

  Best for women with regular cycles. Combine with cervical mucus tracking, basal body temperature or ovulation predictor kits for higher accuracy.

• What signs indicate ovulation?

  Egg-white cervical mucus, mild cramping (mittelschmerz), slight basal body temperature rise, increased libido, breast tenderness. Not all women notice all signs.

• Is this a contraception method?

  No — calendar-based natural family planning has typical-use failure rates of 12-24%. Use proper contraception if pregnancy is not desired.

• Can I influence the baby's sex?

  Some methods (Shettles, Whelan) claim timing influences sex selection but evidence is weak. Ratio remains close to 50/50 regardless of timing.

• What if my cycles are irregular?

  Calendar prediction is less reliable. Track basal body temperature daily and use ovulation predictor kits (LH surge detection) for better accuracy.

• How long does it take to get pregnant?

  About 80% of couples conceive within 6 months of trying; ~90% within a year. After 12 months without success (6 if over 35), consult a fertility specialist.

• Does ovulation always happen?

  Not necessarily. Anovulatory cycles (no ovulation) occur occasionally even in healthy women, more frequently with stress, illness, weight changes, breastfeeding or PCOS.