How is it Calculated?

Doctors calculate your due date using Naegele's Rule. Since most women do not know the exact day of conception, pregnancy is counted from the first day of your last menstrual period (LMP).

The Formula:

Due Date (EDD) = LMP + 280 Days (40 Weeks)

*Note: This assumes a 28-day cycle. Our calculator automatically adjusts for shorter or longer cycles.

Pregnancy Stages

First Trimester

Weeks 1 - 12

Baby's organs develop. You may experience morning sickness and fatigue. It's a critical time for development.

Second Trimester

Weeks 13 - 27

The "Golden Period". Nausea usually fades, and you may feel the baby move for the first time!

Third Trimester

Weeks 28 - 40

Baby grows rapidly. You might feel heavy or uncomfortable. Baby is considered "full term" at 37 weeks.

FAQ

Will my baby be born on this exact date? ▼

Likely not. Only about 4-5% of babies arrive on their due date. Most are born within two weeks before or after.

My periods are irregular, is this accurate? ▼

LMP-based calculation is less accurate for irregular cycles. An early ultrasound (Dating Scan) is the most accurate way to determine gestational age in this case.

How is it calculated for IVF? ▼

For IVF, calculate based on the Transfer Date. If Day 3 transfer, subtract 17 days. If Day 5 (Blastocyst), subtract 19 days to find your "virtual" LMP.

What is "Full Term"? ▼

Pregnancy is considered full term starting at 37 weeks. Babies born after this time are usually fully developed.

Why am I "2 weeks pregnant" at conception? ▼

Because pregnancy dating starts from the start of your last period, which is usually about 2 weeks before you actually conceived.

Can my due date change? ▼

It might change after your 12-week dating scan if the baby measures significantly larger or smaller than expected based on your LMP.

What if I go past my due date? ▼

It's common. Doctors typically allow pregnancy to continue to 41 or 42 weeks before considering induction, provided mom and baby are healthy.

Ultrasound vs. LMP Date? ▼

The ultrasound date is generally more accurate, especially in the first trimester. Doctors usually go by the scan date if there's a discrepancy of more than a week.