Ovulation Calculator
Estimate your ovulation date and fertile window based on your menstrual cycle.
How Ovulation Is Calculated
Ovulation typically occurs about 14 days before your next period starts, regardless of cycle length. The fertile window includes the 5 days before ovulation and the day of ovulation itself.
This calculator uses the standard method: Ovulation Date = Next Period Date - 14 days. The fertile window is estimated as 5 days before ovulation through the day of ovulation (a total of 6 days), based on sperm survival (up to 5 days) and egg viability (24 hours).
About this Calculator
The Ovulation Calculator is a free, easy-to-use tool for fertile, cycle, conception. Simply enter your values and get instant, accurate results — no signup, no ads, no tracking. All calculations run locally in your browser, so your data stays completely private.
Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.