Pregnancy due date calculator
Enter your last period date and get the estimated due date.
Pregnancy due date calculator
This calculator estimates your due date (EDD) from your last menstrual period (LMP), plus your current gestational age and trimester. It’s guidance, not a medical diagnosis.
How it’s calculated (Naegele’s rule)
Due date = last period + 280 days (40 weeks)
Pregnancy is counted from the first day of the last period and lasts about 40 weeks. The real date can vary; most births happen between weeks 37 and 42.
Trimesters
- 1st trimester: weeks 1-13.
- 2nd trimester: weeks 14-27.
- 3rd trimester: weeks 28-40.
Frequently asked questions
What if my cycle isn’t 28 days? Naegele’s rule assumes 28 days; with very different cycles a first-trimester ultrasound is more accurate.
Is it accurate? It’s an estimate; only medical follow-up confirms the date.
Note: general information, not medical advice.