Women's Health
Ovulation Calculator
Track your fertile window and predict ovulation days for family planning.
📅 Cycle Information
Average Cycle Length
days
Typical range: 21-45 days
Period Duration
days
📆 Date Information
Last Period Start
First day of your last menstrual period
Cycle Regularity
Regular cycles are 21-35 days
⚙️ Advanced Options
Cycle 0
Ovulation Day
cycle day
Fertile Window
Next Period
Cycle Day
Fertility Status
💡 Health Tip: The fertile window is typically 5 days before ovulation and the day of ovulation. Sperm can survive up to 5 days in the female reproductive tract.
📊 Fertility Calendar
Fertile Ovulation Period Other

📊 Cycle Prediction Schedule

Date Cycle Day Status Fertility

How the formula works

Ovulation Day = Cycle Length − 14  |  Fertile Window = Ovulation Day − 5 to Ovulation Day
  • Ovulation = Release of egg from ovary (typically 14 days before next period)
  • Fertile Window = 5 days before ovulation + day of ovulation (6 days total)
  • Luteal Phase = Days after ovulation until next period (typically 14 days)
  • Cycle Day 1 = First day of menstrual bleeding
  • Most Fertile Days = Day before ovulation and day of ovulation