Ovulation Calculator

Find your fertile window and best days to conceive

First day of your last period

Average cycle length (days)

Track your cycle for 2–3 months for the best accuracy

Luteal phase length (days)

Most women have a 14-day luteal phase. Leave as default if unsure.

Estimated ovulation date

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🌟 Your fertile window (best days to conceive)

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The 6 days around ovulation when pregnancy is most likely

Next period expected

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Days until ovulation

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Cycle length

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Luteal phase

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Next 3 cycles — ovulation dates

⚠️ This calculator provides estimates based on average cycle data. Every woman's cycle is different. These are not medical predictions. Please consult a healthcare provider for personalised fertility advice.

Understanding Ovulation

When does ovulation occur?

Ovulation typically occurs 14 days before the next period (the luteal phase). For a 28-day cycle, that's day 14. For a 32-day cycle, it's around day 18. The egg is viable for 12–24 hours after release.

What is the fertile window?

The fertile window spans 6 days — the 5 days before ovulation plus the day of ovulation itself. Sperm can survive in the reproductive tract for up to 5 days, so having intercourse in this window maximises the chance of conception.

How to confirm ovulation?

Ovulation predictor kits (OPKs) detect the LH surge that occurs 24–36 hours before ovulation. Basal body temperature (BBT) charting shows a slight temperature rise after ovulation. Cervical mucus becomes clear and stretchy (like egg whites) near ovulation.