Due Date Calculator
Calculate the expected due date of your baby using Naegele's rule. With clear explanations, recommendations and comparison values.
Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.
Frequently Asked Questions
How is the due date calculated?
The due date is calculated using Naegele's rule: first day of last period plus 7 days minus 3 months plus 1 year. The standard pregnancy duration is 280 days (40 weeks) from the last menstrual period.
How accurate is the calculated due date?
Only about 4% of babies are born on their calculated due date. About 90% are born within two weeks before or after. Ultrasound dating in the first trimester is the most accurate method.
What is the Due Date Calculator?
The due date calculator computes the expected delivery date based on the first day of the last menstrual period or the conception date.
How does the Due Date Calculator work?
Enter the first day of your last period. Using Naegele's rule: due date = first day of last period + 7 days - 3 months + 1 year. With a known conception date: due date = conception + 266 days. The current pregnancy week is also shown.
Key Data and Facts
Naegele's rule: last period start + 7 days - 3 months + 1 year. Pregnancy duration: 280 days = 40 weeks. Only about 4% of babies are born on the calculated date.
Step-by-Step Guide
How to calculate den Geburtstermin step by step: 1. Ersten day der letzten Periode enter: Dieses Datum ist die Grundlage der Naegele-Regel. 2. Naegele-Regel anwenden: ET = Erster day der letzten Periode + 7 days - 3 Monate + 1 year. Alternativ: ET = Erster day der letzten Periode + 280 days. 3. Bei bekanntem Zeugungsdatum: ET = Konzeptionsdatum + 266 days (38 Wochen). 4. Aktuelle SSW ablesen: Der Rechner zeigt die aktuelle Schwangerschaftswoche und den genauen Schwangerschaftstag an. Beispiel: SSW 12+3 bedeutet 12. week und 3 days. 5. Trimester-Einteilung: 1. Trimester SSW 1-12, 2. Trimester SSW 13-27, 3. Trimester SSW 28-40. 6. Beachten Sie: Nur ca. 4 % der Kinder kommen am errechneten Termin. Die meisten Geburten finden zwischen SSW 38 und SSW 42 statt. Der Frauenarzt kann den Termin per Ultraschall-Messung praezisieren.
Calculation Example
Letzte Periode: 15. Januar 2026. ET nach Naegele: 15 + 7 = 22, Januar - 3 Monate = Oktober, + 1 year: 22. Oktober 2026. Schwangerschaftsdauer: 280 days.
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