How accurate is a due date calculator?

It is an estimate. Only about 4-5% of babies are born on their exact due date. Most are born within two weeks before or after this date (38-42 weeks).

What is Naegele's Rule?

It is the standard medical formula used by doctors: Take the first day of the LMP, add 7 days, subtract 3 months, and add 1 year.

Why does pregnancy count calculate from before conception?

Because exact ovulation dates are hard to pinpoint, doctors measure 'Gestational Age' starting from the first day of your last period, which is roughly 2 weeks *before* you actually conceived.

Can an ultrasound change my due date?

Yes. An early dating scan (usually at 8-12 weeks) is more accurate than the LMP method. If the ultrasound date differs from the LMP date by more than a week, your doctor will likely update your official due date.

Pregnancy Due Date Calculator | Estimate Baby's Arrival | Finmato

Your Personal Timeline

"When are you due?" It's the first question everyone asks. Our Pregnancy Due Date Calculator gives you that answer instantly, along with a detailed breakdown of where you are in the journey right now.

Knowing your Estimated Due Date (EDD) isn't just about marking a calendar; it helps you schedule prenatal tests (like the anatomy scan at 20 weeks), plan your maternity leave, and track your baby's weekly development.

The Magic of 40 Weeks

Why is pregnancy 40 weeks long if 9 months is only roughly 39 weeks?

Gestational vs. Fetal Age

Gestational Age (Used by Doctors)

Starts from the first day of your last period. This includes the ~2 weeks before you were even pregnant. It is easier to track because most women know when their period started.

Fetal Age (Actual Age)

Starts from the moment of conception (fertilization). This is usually about 2 weeks less than gestational age.

Understanding Trimesters

Your due date helps you divide the massive 9-month journey into three distinct phases:

First Trimester (Weeks 1-13): The "invisible" phase. Rapid development of vital organs. Often accompanied by morning sickness and fatigue.
Second Trimester (Weeks 14-27): The "Golden Period." Energy usually returns, and you will likely feel the baby kick for the first time.
Third Trimester (Weeks 28-40+): The home stretch. The baby gains rapid weight, and you start preparing for labor.

Planning Work Leave

Most employers require you to specify a start date for maternity leave. Your EDD gives you a target to plan backward from.

Scheduling Travel

Most airlines restrict travel after 36 weeks. Knowing your exact week allows you to plan your "Babymoon" safely.

Grandparent Visits

Family inevitably wants to know when to book flights. Giving them a "window" around your EDD helps manage expectations.

Frequently Asked Questions

What if I have irregular periods?

Calculators rely on a regular 28-day cycle. If yours are irregular, the estimate might be off by a week or more. In this case, an ultrasound is the only reliable way to date the pregnancy.

Is it considered "Late" if I pass my due date?

Not immediately. A pregnancy is considered "Full Term" anywhere from 39 to 40 weeks and 6 days. You are only considered "Post-term" or "Overdue" after 42 weeks.

Does this calculator work for IVF?

For IVF, the "egg retrieval" or "transfer date" is more accurate than LMP. Doctors usually add 266 days (38 weeks) to the egg retrieval date to find the EDD.

Medical Disclaimer

This tool is for educational purposes only. It is not a substitute for professional medical advice. Always consult your OB-GYN or midwife.

Data Privacy

We do not store your cycle dates. This tool runs entirely in your browser.

Pregnancy Due Date Calculator

Estimated Due Date