Ovulation Calculator

Calculate your ovulation date and fertile window based on your menstrual cycle. Plan or avoid pregnancy with your personalised fertility calendar.

Please select your LMP date.

What Is Ovulation?

Ovulation is the release of a mature egg from the ovary, typically occurring once per menstrual cycle. It marks the only time during a cycle when pregnancy is possible. The egg survives for just 12–24 hours after release, but sperm can live in the female reproductive tract for up to 5 days — making the 5 days before ovulation and the day of ovulation the fertile window.

When Does Ovulation Occur?

In a standard 28-day cycle, ovulation typically occurs around day 14. However, this varies significantly between women and even between cycles in the same woman. The key is that ovulation occurs approximately 14 days before the next expected period (the luteal phase is relatively constant at 14 days), regardless of cycle length.

Signs of Ovulation

Common physical signs include: a change in cervical mucus (becomes clearer and more stretchy, like raw egg white); a slight rise in basal body temperature (0.2–0.5°C) after ovulation; mild one-sided pelvic pain (mittelschmerz); and increased libido. Ovulation predictor kits (OPKs) detect the LH surge that precedes ovulation by 24–36 hours.

Frequently Asked Questions

Can I get pregnant just before my period?
It is unlikely but possible if you have a short cycle or irregular ovulation. If ovulation occurs later than usual, the fertile window can overlap with days typically considered safe.
What if my cycle is irregular?
Irregular cycles make calendar-based ovulation prediction less reliable. Tracking basal body temperature (BBT), cervical mucus, and using OPKs provides more accurate ovulation detection for irregular cycles.
How many days am I fertile each cycle?
The fertile window is approximately 6 days: the 5 days before ovulation and ovulation day itself. Peak fertility is the 1–2 days immediately before ovulation.
Medical Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for health decisions.