Pregnancy Due Date Calculator

Calculate due date, weeks pregnant and trimester from LMP, conception or ultrasound.

Enter a date to see your due date
Weeks pregnant
Trimester
Days to go
Est. conception

How Due Date is Calculated

Your estimated due date (EDD) is the day your baby is expected to be born. It's typically calculated as 40 weeks (280 days) from the first day of your last menstrual period (LMP) — this is Naegele's rule.

Only about 5% of babies are born on their exact due date. Most arrive within 2 weeks before or after.

Pregnancy Trimesters

TrimesterWeeksHighlights
First1–13Confirmation, early symptoms, first ultrasound
Second14–27Baby bump visible, feeling first movements (~20 weeks)
Third28–40Faster growth, preparation for birth

Pregnancy Term Definitions

  • Early term: 37 weeks 0 days – 38 weeks 6 days
  • Full term: 39 weeks 0 days – 40 weeks 6 days ✅
  • Late term: 41 weeks 0 days – 41 weeks 6 days
  • Post term: 42 weeks 0 days and beyond

⚕️ Medical disclaimer: This calculator provides estimates only. Please consult your obstetrician for personalized prenatal care.

Frequently asked questions

How is due date calculated?
Due date = first day of LMP + 280 days (40 weeks) — Naegele's rule.
Is due date accurate?
It's an estimate. Only ~5% of babies are born on the exact date. Ultrasound-based dating in the first trimester is more accurate for irregular cycles.
When does 2nd trimester start?
Week 14.
When is baby full-term?
39–40 weeks.
Is my data stored?
No — everything runs in your browser and nothing is saved.