Ovulation Calculator

Ovulation typically occurs 14 days before your next period — not 14 days after your last period started. For a standard 28-day cycle, this is around day 14. For a 30-day cycle, ovulation falls around day 16. For a 26-day cycle, around day 12. The luteal phase (ovulation to next period) is consistently 14 days across most women, while the follicular phase (period to ovulation) varies with cycle length.

The fertile window is the 6-day period ending on the day of ovulation. This includes the 5 days before ovulation and ovulation day itself. Sperm can survive inside the female reproductive tract for up to 5 days, while an egg lives only 12–24 hours after release. Your two highest-probability days are the day before ovulation and the day of ovulation — conception rates on these days can reach 25–30%.

This calculator provides an estimate based on your reported cycle length and last period. It assumes a regular cycle with ovulation 14 days before your next period. Accuracy depends on cycle regularity — stress, illness, travel, hormonal changes, and conditions like PCOS can shift ovulation significantly. For the most accurate tracking, combine this calculator with basal body temperature charting and LH ovulation test strips.

Common ovulation signs include: egg-white cervical mucus (clear, slippery, stretchy), a slight rise in basal body temperature (0.2–0.5°C), mild one-sided pelvic pain (mittelschmerz), increased libido, breast tenderness, and a slight LH surge detectable with ovulation test strips. Not all women experience noticeable symptoms, which is why tracking multiple signs gives the clearest picture.

It's very unlikely but not impossible. The fertile window is the only time conception can occur, since sperm must reach a viable egg. However, if your cycle is irregular and you ovulate earlier or later than expected, intercourse at seemingly 'safe' times can result in pregnancy. The fertile window calculation here is an estimate — irregular cycles require closer monitoring.

Research shows the highest pregnancy rates come from intercourse on the two days before ovulation and the day of ovulation itself. Daily or every-other-day intercourse during the fertile window maximizes exposure. Having intercourse every other day maintains sperm quality better than daily intercourse for men with lower sperm counts. Starting 4–5 days before your estimated ovulation date gives a good buffer for cycle variation.

Polycystic Ovary Syndrome (PCOS) is one of the most common causes of irregular ovulation or anovulation (no ovulation). Women with PCOS may have cycles of 35–90+ days or no cycle at all, making calendar-based ovulation prediction unreliable. PCOS affects roughly 1 in 10 women of reproductive age. Tracking with LH strips and basal body temperature is especially important with PCOS — and a fertility specialist can provide tailored guidance.