🌸 Women's Health

Ovulation Calculator

Predict your ovulation date and fertile window based on your last menstrual period and cycle length. Includes 3-cycle forecast.

Your Cycle Details

Enter your last period and cycle length

First day of last menstrual period

Average cycle length (days)

Luteal phase length (days)

Enter your cycle details

Select your last period date to calculate ovulation and your fertile window.

Menstrual Cycle Phases

Phase	Typical Days
Menstruation	Days 1–5
Follicular Phase	Days 1–13
Ovulation	~Day 14
Luteal Phase	Days 15–28

Frequently Asked Questions

When is the fertile window?

The fertile window spans the 5 days before ovulation plus the day of ovulation — 6 days in total. Sperm can survive up to 5 days, so intercourse before ovulation can still result in fertilization.

When does ovulation occur?

Ovulation typically occurs 14 days before your next period. For a 28-day cycle this is around day 14; for a 35-day cycle it would be around day 21.

How accurate is this calculator?

This calculator assumes a regular cycle. Irregular periods, PCOS, stress, and other factors can shift ovulation timing significantly. For fertility concerns, consult a gynecologist.