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Online Ovulation Calculator

The Ovulation Calculator helps you predict your likely fertile window and ovulation dates, along with other important cycle milestones. These estimates are based on the date of your last menstrual period. Please remember, this tool is designed for guidance only and should not be relied upon as a method of birth control.

Ovulation Calculator | Fertile Window & Next Period Predictor

Ovulation Calculator

Enter the first day of your last period and your average cycle length. This calculator will estimate your ovulation day, fertile window, and next period.

⚠️ This calculator provides an estimate only. Cycles can vary due to stress, illness, or other factors. Consult a doctor for medical advice.

Frequently Asked Questions

How does this ovulation calculator work?

We calculate ovulation as about 14 days before your next period. Fertile days include the 5 days before ovulation plus the day of ovulation.

What is the luteal phase?

The luteal phase is the time between ovulation and the start of your next period. It usually lasts around 14 days but can range from 12–17.

Can I use this calculator for birth control?

This tool is for educational use only. It is not a reliable method of contraception.

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