Predict your ovulation and fertile window with ease.
Introduction
Knowing the ovulation period is key for conception or contraception. This calculator estimates ovulation and the fertile window from the last menstrual period (LMP) and cycle length, with a visual calendar, history tracking, and cycle chart.
Your Ovulation Details
Ovulation Date:
Fertile Window:
Next Period:
Cycle Calendar
Ovulation Date
Fertile Window
Calculation History
Timestamp
LMP Date
Cycle Length
Ovulation Date
Action
How to Use
Enter the first day of the last menstrual period (LMP).
Input average cycle length (20–45 days).
Click Calculate to see ovulation date, fertile window, and next period.
Review the calendar and chart; save to history if desired.
About the Calculation
Ovulation is estimated as LMP + (cycle length − 14), assuming a 14‑day luteal phase. The fertile window spans the five days before ovulation plus the ovulation day. Next period is LMP + cycle length.