Ovulation Calculator

This ovulation calculator estimates your fertile window using the standard formula: ovulation occurs approximately 14 days before your next expected period, regardless of cycle length. For a 28-day cycle, ovulation happens around Day 14. For a 32-day cycle, it happens around Day 18.

The Fertile Window Explained

An egg survives 12–24 hours after ovulation, but sperm can live in the fallopian tubes for up to 5 days. This means you can conceive if you have intercourse in the 5 days before ovulation or on the day of ovulation itself. That is your 6-day fertile window.

Signs You're Ovulating

• Cervical mucus changes: Becomes clear and stretchy like raw egg white around ovulation.
• Basal body temperature (BBT): Drops slightly just before ovulation, then rises ~0.2–0.5°C (0.4–1°F) after.
• Ovulation pain (Mittelschmerz): A dull ache or twinge on one side of the lower abdomen.
• LH surge: A positive ovulation predictor kit (OPK) test detects the LH hormone surge 24–36 hours before ovulation.
• Breast tenderness or increased sex drive around mid-cycle.

When to See a Doctor

If you have been trying to conceive for 12 months (or 6 months if you're over 35) without success, consult a fertility specialist. Conditions like PCOS, thyroid disorders, or endometriosis can affect ovulation and are highly treatable.

This calculator provides an estimate based on average cycle statistics. Actual ovulation timing varies. It is not a substitute for medical advice or contraception.