Ovulation Calculator

Calculate your ovulation date and fertile window based on your cycle length.

First Day of Last Period

Cycle Length (days)

Daily nutrition made simple — vitamins, probiotics & adaptogens in one scoop.

How it works

This calculator uses the calendar method: ovulation occurs approximately 14 days before your next period. For a 28-day cycle, that is day 14; for a 32-day cycle, day 18. The fertile window spans 5 days before ovulation, ovulation day, and 1 day after.

Calculate Ovulation: How to Determine Your Fertile Days →

Calculate your ovulation with the calendar method. Fertile window, cycle length, luteal phase and tips for natural family planning.