Pregnancy Due Date Calculator
Comfort Through Every Trimester
Sleep better with a full-body maternity pillow that supports your belly, back, hips and legs and adjusts as your pregnancy progresses.
Shop Momcozy Pregnancy PillowAbout Pregnancy Due Date Calculator
The Pregnancy Due Date Calculator estimates your estimated due date (EDD) based on either your last menstrual period (LMP) or your conception date. The LMP method follows Naegele’s rule — adding 280 days (40 weeks) to the first day of your last period — and automatically adjusts for menstrual cycle lengths other than 28 days. If the conception date is known, the calculator adds 266 days to estimate your expected delivery date.
The resulting EDD is an estimate, not a prediction — only a small percentage of pregnancies reach delivery exactly on the due date. Most full-term births occur within about two weeks before or after the calculated date.
How to use this Pregnancy Due Date calculator
- Select whether you know your LMP or conception date.
- Enter the date (and your usual cycle length if using the LMP option).
- Click Calculate to view your estimated due date, gestational age, and current trimester.
Notes
- Early ultrasound dating can refine the due-date estimate if there’s uncertainty about LMP or irregular cycles.
- Cycle-length adjustment: if your cycle is longer than 28 days, the due date shifts later by that difference; if shorter, it shifts earlier.
- This calculator provides general educational information and should not replace medical evaluation by your healthcare provider.
FAQ
- How is the due date calculated? The calculator uses Naegele’s rule — adding 280 days (40 weeks) to the first day of your last menstrual period (LMP).
- Can I calculate from conception date? Yes. Conception typically occurs about 14 days after LMP in a 28-day cycle. The calculator can also estimate due date based on conception or IVF transfer date.
- What if my cycle isn’t 28 days? The calculator adjusts automatically by adding or subtracting days based on your average cycle length.
- How accurate is the predicted due date? Due dates are estimates. Only about 4% of babies are born exactly on their predicted date; most arrive within 2 weeks before or after.
- What is considered a full-term pregnancy? A full-term pregnancy is between 37 and 42 weeks of gestation.
- Should I rely on this calculator for medical decisions? No. It’s for general informational use only — consult your doctor or midwife for personalized care.
Disclaimer
The calculators provided on this site are for educational and informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult your prenatal care provider for guidance about dating, screenings, and pregnancy care.