Know your due date, week by week
Last Menstrual Period
Uses Naegele's Rule: LMP + 280 days (40 weeks).
Your Results
Estimated Due Date
Thursday, February 4, 2027
224 days to go
20% complete
Pregnancy Milestones
Medical disclaimer: This calculator uses Naegele's Rule and is intended for informational purposes only. Only a licensed healthcare provider can confirm your due date. Actual due dates may vary based on cycle length and ultrasound measurements.
Our free pregnancy due date calculator uses Naegele's Rule — the same method OBs use — to estimate your due date from the first day of your last menstrual period (LMP). Enter your LMP and instantly see your estimated due date, current pregnancy week and day, trimester, percent complete, approximate conception date, and a full timeline of key pregnancy milestones.
The calculator uses Naegele's Rule: your estimated due date (EDD) is the first day of your last menstrual period (LMP) plus 280 days (40 weeks). This is the standard method used by obstetricians worldwide and assumes a 28-day menstrual cycle.
Naegele's Rule gives a statistically reliable estimate, but only about 5% of babies are born exactly on their due date. Accuracy depends on your cycle length and confirmation by early ultrasound. Your healthcare provider may adjust your EDD based on first-trimester measurements.
Pregnancy weeks are counted from the first day of your LMP, not from conception. So at the moment of fertilization (around day 14), you are already considered 2 weeks pregnant in standard obstetric counting. Enter your LMP above to see your exact week and day.
The first trimester covers weeks 1–13, the second trimester weeks 14–26, and the third trimester weeks 27–40. Each trimester brings distinct developmental milestones; the calculator shows which trimester you are currently in alongside upcoming milestone dates.