Pregnancy Calculator

Calculate your estimated due date, current week of pregnancy, trimester, and key milestones. Enter the first day of your last menstrual period (LMP) or your conception date for a complete pregnancy timeline.

Due Date Calculator

How Due Date is Calculated

Naegele's Rule (from LMP): Due Date = LMP + 280 days (40 weeks) From conception date: Due Date = Conception + 266 days (38 weeks) Trimester boundaries: 1st Trimester: Weeks 1–13 2nd Trimester: Weeks 14–26 3rd Trimester: Weeks 27–40

Pregnancy Milestones

WeekMilestone
Week 4Missed period, home test positive
Week 8Heartbeat detectable by ultrasound
Week 12End of 1st trimester, NT scan
Week 20Anatomy scan / gender ultrasound
Week 24Viability milestone
Week 283rd trimester begins
Week 37Full term
Week 40Due date

Frequently Asked Questions

How accurate is an estimated due date?+
Only about 5% of babies are born on their exact due date. The due date is an estimate — most babies arrive within 2 weeks before or after. An early ultrasound (before 14 weeks) is the most accurate way to confirm gestational age.
What is the LMP method?+
The LMP (Last Menstrual Period) method calculates due date by adding 280 days (40 weeks) to the first day of your last period. This is the standard method used by most healthcare providers, based on Naegele's Rule from 1850.

Related Calculators

Age Calculator Age Difference Date Calculator Days Calculator BMI Calculator