Free Ovulation & Fertility Calculator Online
Predict ovulation date, fertile window (6-day peak window), and expected next period based on last menstrual period date and average cycle length. — 100% free online utility, zero sign-up, zero paywalls, and private client-side processing.
How It Works
Enter Last Period Date
Input the first day of your last menstrual period.
Enter Cycle Length
Input your average menstrual cycle length in days (typically 21–35 days).
View Fertile Window
See predicted ovulation date, 6-day fertile window, and next expected period.
Frequently Asked Questions
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