Ovulation Calculator
Our free online Ovulation Calculator helps you discover your most fertile days of the month. By entering the first day of your last menstrual period and your average cycle length, we can pinpoint your exact fertile window to maximize your chances of getting pregnant.
The Science Behind Ovulation
Ovulation occurs when a mature egg is released from the ovary, pushed down the fallopian tube, and is available to be fertilized. Approximately every month an egg will mature within one of your ovaries. As it reaches maturity, the egg is released by the ovary where it enters the fallopian tube to make its way towards waiting sperm and the uterus.
The lining of the uterus has thickened to prepare for the fertilized egg. If no conception occurs, the uterine lining, as well as blood, will be shed. The shedding of an unfertilized egg and the uterine wall is the time of menstruation.
How to Use This Calculator
- First day of your last period: Select the first date that your most recent menstrual cycle began.
- Average Cycle Length: Enter the number of days your cycle typically lasts. The default average is 28 days.
- Calculate: Instantly see your estimated ovulation date, your 6-day fertile window, and your expected date for your next period.
Understanding Your Fertile Window
Your fertile window refers to the days in your menstrual cycle when pregnancy is possible. The "fertile window" depends on the length of the menstrual cycle, which varies among women. The fertile window is the day an egg is released from the ovary (ovulation) and the five days beforehand. Having sex (intercourse) during this time gives you the best chance of getting pregnant.