Introduction

If you plan to conceive a child, you have probably asked yourself: “When are my most fertile days?”. With our ovulation calculator, you will know when you will likely ovulate in the subsequent three cycles.

But beware, this ovulation calculator is provided for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. The results are based on statistical formulas and user-entered data and cannot guarantee the prediction of ovulation or fertile periods with certainty. Everybody is unique, and many factors (hormonal, medical, psychological) can influence the menstrual cycle. We encourage you to consult a gynecologist or other qualified healthcare professional with any questions regarding reproductive health.

This tool has been developed with attention to the quality of available scientific sources but does not represent personalized medical advice.

Ovulation and the Fertile Window

Ovulation is the release of an egg cell (ovum, oocyte, ovum, oocyte) from one of the ovaries. It usually occurs about two weeks before the next menstruation begins, in the middle of the menstrual cycle.

You are most fertile during ovulation: to be more precise, during the so-called fertile window. This begins seven days before ovulation since sperm can survive in your body for up to seven days.

Because the egg has a much shorter lifespan, the fertile window ends 24 hours after ovulation.

The data needed to estimate ovulation.

To use our ovulation calculator, you need to enter two pieces of information about your menstrual cycle:

1- The duration of the cycle

A typical cycle lasts about 28 days. 

However, it is perfectly normal to have a slightly longer or shorter cycle, for example, lasting 27 or 30 days. 

If you’re unsure of your exact cycle length (or if you have irregular cycles), stick with the default length of 28 days.

2- The start date of your last menstrual cycle

It is calculated starting from the first day of menstrual flow, also known as the first day of the cycle.

The calculator and the due date

An additional feature of this ovulation calculator is the estimated due date, the estimated day of your baby’s birth if you were to conceive during the indicated time frame.

This estimate is based on the assumption that the pregnancy lasts 280 days (40 weeks). However, you should be aware that only 5% of all women give birth on the exact date. Your baby could be born a little earlier or later than the indicated date, and the pregnancy would still be considered full-term.

A full-term pregnancy is defined as one in which delivery occurs between the 37th and 41st week.

If the birth occurs before the 37th week, it is called preterm birth or premature birth, while if the birth occurs after the 42nd week, it is called post-term pregnancy.