Due Date Calculator

Calculate when your child will be born!

It usually takes 266 days from conception to the birth of your child. If you do not know the day of conception, we can also calculate the date based on the first day of the last menstrual period. If this is the case for you, please tick the small box!

Calculate due date

You’re pregnant? Congratulations! You are definitely looking forward to the calculation of the expected date of birth full of anticipation. During your first visit, your gynecologist will use an ultrasound to determine the progress of the pregnancy.

Regardless of this ultrasound diagnosis, the expected date of birth can also be determined using the so-called Naegele rule. Our due date calculator is based on this rule. She calculates the due date based on the date of fertilization. Specifying this date gives the most accurate result. If it is not known, the first day of the last period can be used as an alternative.

Naegele’s rule with the day of fertilization

Due date = date of fertilization – 3 months – 7 days + 1 year

Naegele’s rule with the date of the first day of the last period

Due Date = Date of the first day of the last period – 3 months + 7 days + 1 year

If the cycle length is longer or shorter than 28 days, this can be taken into account when calculating the due date. If the cycle is longer, the additional days are added, if it is shorter, the days are subtracted.

Birth date not predicted

However, the due date calculator only provides an approximate value and not an exact prediction. Adding to the inaccuracy is that many women do not know the exact date of conception or when their last period started. The course of pregnancy and the development of the baby can also be very different. For this reason, the appointment is repeatedly checked by ultrasound during the course of the pregnancy and corrected if necessary.

What deviation from the due date is normal?

Only four percent of all children are actually born on their due date. More than two thirds of the children are born between 10 days before and 10 days after the expected date. In most cases, a longer or shorter wearing time is not a problem at all. If problems do arise, they are almost always detected during pregnancy during prenatal care and the other prenatal diagnostic tests and then monitored further.