About

Knowing your estimated due date (EDD) is the first step in preparing for your baby's arrival. Doctors primarily use Naegele's Rule, which calculates the due date based on the first day of your last menstrual period (LMP). Accurate dating is essential for scheduling prenatal screenings, such as the nuchal translucency scan (11-14 weeks) and the anatomy scan (18-22 weeks).

This tool goes beyond simple date addition. It helps you visualize the timeline of your pregnancy, identifying key milestones:

EDD = LMP + 280 days

It also provides a fun Fruit Size Comparison to help you visualize your baby's growth week by week.

Formulas

The calculator uses the standard medical convention of a 280-day gestation period (40 weeks) from the LMP. Conception is estimated to occur approximately 14 days after the LMP in a standard 28-day cycle.

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Conception ≈ LMP + 14 daysDue Date = LMP + 9 months + 7 days

Reference Data

Trimester	Weeks	Key Developments
First	1 - 12	Heartbeat detected, organs form. Highest fatigue.
Second	13 - 26	Baby moves (quickening), gender reveal possible.
Third	27 - 40	Rapid weight gain, lungs mature, head engages.
Full Term	37 - 40	Baby is ready for birth.
Post Term	41 - 42	Monitoring required; induction may be discussed.

Frequently Asked Questions

Only about 5% of babies are born on their exact due date. Most are born within two weeks before or after. An early ultrasound is the most accurate way to date a pregnancy.

If your cycle is irregular or you don't know your LMP, a doctor can estimate the date using an ultrasound measurement of the fetus (Crown-Rump Length).

Conception usually happens during ovulation, which is around day 14 of a 28-day cycle. However, sperm can survive for up to 5 days, so the "fertile window" is wider than just the day of ovulation.

It is an ancient chart that supposedly predicts gender based on the mother's lunar age and month of conception. It is for entertainment purposes only and has no scientific basis.