Ovulation and Period Calculator

Our ovulation and period calculator helps you determine key dates related to your menstrual cycle and fertility. Whether you're tracking ovulation, predicting your next period, or identifying your fertile window, our calculator provides accurate results. Simply input your information and let our calculator do the rest.

Last period

Choose the starting date of your most recent menstrual circle.


June 2024
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Cycle length

Enter the number of days in your menstrual cycle.


Quick selections

Step 1

Enter the start date of your last period and your cycle duration to calculate the following data.

Fertile window

The fertile window is the time period in which a woman is most likely to conceive, typically occurring around the time of ovulation.

Ovulation date

Ovulation date is the day in a woman's menstrual cycle when an egg is released from the ovary and can potentially be fertilized.

Next period date

The Next Period Date is the date when a women's menstrual cycle is expected to begin again after the previous period.

Pregnancy test date

A pregnancy test date refers to the date on which a woman takes a pregnancy test to determine if she is pregnant.

Expected due date

The expected due date (EDD) is the date that a pregnant woman's baby is expected to be born. The actual due date may vary by a few days or weeks.

How to calculate

Fertile window

The fertile window is the time when you are most likely to conceive. It starts 5 days before ovulation and ends 1 day after ovulation. To calculate your fertile window, add 5 days to your ovulation date. For example, if your ovulation date is day 14, your fertile window would be from day 9 to day 15.

Ovulation date

To calculate the ovulation date, you will need to know your cycle length. The average cycle length is 28 days, but it can vary from person to person. To calculate your ovulation date, subtract 14 days from the length of your cycle. For example, if your cycle is 28 days, your ovulation date would be day 14.

Next period date

To calculate your next period date, simply add your cycle length to the start date of your last period. For example, if your last period started on day 1 and your cycle length is 28 days, your next period would start on day 29.

Pregnancy test date

A pregnancy test can usually detect pregnancy after a missed period. To calculate when to take a pregnancy test, add 14 days to the end of your fertile window. For example, if your fertile window ends on day 15, you would take a pregnancy test on day 29.

Expected due date

To calculate your expected due date, add 280 days (40 weeks) to the first day of your last period. For example, if your last period started on day 1, your expected due date would be 180 days later on day 281.