Question 1

How is the estimated due date calculated?

Accepted Answer

Using the Naegele rule, the calculator adds 280 days (40 weeks) to the first day of your last period. If your cycle length differs from 28 days, the date is corrected accordingly. If you know the day of conception, 266 days are added; with IVF the date is derived exactly from the transfer date.

Question 2

Will my baby really arrive on the due date?

Accepted Answer

Only about 4% of babies are born exactly on the due date. Most arrive in the two weeks before or after. The due date is therefore a point of reference, not a fixed date. The ultrasound dating done by your doctor is the decisive figure.

Question 3

Why are pregnancy weeks counted from the last period?

Accepted Answer

The exact moment of conception usually cannot be determined, whereas the first day of the last period is easy to remember. That is why the medical pregnancy week (SSW) is counted from that day. As a result, you are already in the 3rd week at conception — by this count a pregnancy lasts 40 weeks.

Question 4

What does the notation "12+3" mean?

Accepted Answer

The "week + day" notation states the completed pregnancy weeks and the additional days. "12+3" therefore means 12 full weeks and 3 days — you are then in the 13th week. The calculator shows you this figure automatically for today.

Question 5

When does maternity protection start?

Accepted Answer

Under § 3 of the German Maternity Protection Act, the protection period starts six weeks before the due date and ends eight weeks after birth. For premature and multiple births, the period after birth is extended to twelve weeks. The calculator shows the expected dates based on the due date.

Question 6

Is my data stored?

Accepted Answer

No. The entire calculation runs directly in your browser. Your sensitive health data as defined by Art. 9 GDPR is never sent to a server, stored or analysed. Only if you share your result via a link are the values contained in that address — nowhere else.

Guide: Due Date Calculator

Calculating Your Due Date: How the Naegele Rule Works

Understanding Pregnancy Weeks (SSW)

The Three Trimesters: What Happens in Each Phase of Pregnancy

Calculating Maternity Protection: Dates, Start and End

Overdue: What Happens When You Pass Your Due Date

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