Pregnancy Due Date Calculator

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Medical disclaimer: This calculator is for informational and educational purposes only and is not medical advice. Always consult a qualified healthcare professional for medical decisions.

First day of your last menstrual period

Average cycle length (days)

Most cycles are 21-45 days. Uses Naegele's rule, adjusted for your cycle length.

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What is the Pregnancy Due Date Calculator?

The Pregnancy Due Date Calculator is a free online tool that estimates your baby's delivery date from the first day of your last menstrual period. A full-term pregnancy lasts about 280 days or 40 weeks from that date, a method known as Naegele's rule that doctors have used for over a century. Knowing your estimated due date, or EDD, anchors your entire pregnancy: it schedules ultrasounds, screens for developmental milestones and tells you which week you are in at any moment.

Beyond the headline date, this calculator maps your journey week by week, showing your current trimester, how many weeks remain, and the key checkups typically scheduled at each stage. Only about 5 percent of babies arrive exactly on their due date, with most coming within two weeks on either side, but the EDD remains the essential reference your care team works from.

How to Use the Pregnancy Due Date Calculator

Enter your last period date: Type the first day of your last menstrual period using the date picker.
Confirm cycle length: Adjust from the default 28 days if your cycles are regularly shorter or longer.
Click Calculate: Your estimated due date appears instantly with the conception estimate.
Read your timeline: See your current week, trimester, days remaining and countdown.
Save the milestones: Note the suggested dates for first ultrasound, anatomy scan and glucose screening to discuss with your doctor.

Key Benefits

Naegele's rule accuracy: Uses the same 280-day method your obstetrician starts with.
Cycle-length aware: Adjusts for cycles that are not exactly 28 days.
Week-by-week map: Current week, trimester and countdown in one view.
Checkup guide: Typical screening windows matched to your dates.
Free with no signup: Private calculations, nothing stored or shared.

Pro Tips

First-trimester ultrasound rules: An early dating scan measures the baby directly and can refine or replace the LMP-based date.
Irregular cycles need scans: If your periods are irregular, treat the calculator date as provisional until an ultrasound confirms it.
Count from LMP, not conception: Pregnancy weeks start at your last period, so you are already considered 2 weeks pregnant at ovulation.
Share with your partner: A shared countdown makes appointments and planning easier for both of you.

Frequently Asked Questions

How accurate is the due date?

It is an estimate. About 80 percent of babies arrive within two weeks before or after the EDD, and only 5 percent on the exact day.

What if I do not remember my last period?

Use your best estimate for now, but ask your doctor for an early ultrasound, which dates the pregnancy from the baby's measurements.

Does cycle length change the due date?

Yes. Longer cycles push ovulation later, moving the due date back; shorter cycles move it earlier. The calculator adjusts for this.

Can the due date change later?

Yes. If a first-trimester ultrasound disagrees by more than a few days, your doctor will update the EDD to the scan-based date.

Related Tools

Plan fertile days with the Ovulation Calculator, track your age milestones using the Age Calculator, and split timelines with the Percentage Calculator.

Medical Disclaimer: This calculator is for informational and educational purposes only and is not medical advice. Due dates are estimates and every pregnancy is unique. Always consult your obstetrician, midwife or other qualified healthcare professional for prenatal care.

When it comes to your health, the right dates bring peace of mind. Expecting parents sharing their journey online can rely on FistHost web hosting, with plans from $0.99/mo and a free domain included.

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