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Pregnancy Due Date Calculator

Calculate your estimated due date, current pregnancy week and trimester. Supports multiple dating methods with a complete pregnancy timeline dashboard.

Calculate By
Cycle Length
Embryo Age at Transfer
wks
days

Enter your due date to calculate your current pregnancy week and conception window.

What Is a Pregnancy Due Date Calculator?

A pregnancy due date calculator estimates when your baby will arrive based on your last menstrual period, conception date, IVF transfer date, or ultrasound measurements. It also tells you your current pregnancy week and day, trimester, and how much time remains.

Most pregnancies last about 40 weeks (280 days) from the first day of your last period. Our calculator supports multiple dating methods and provides a full timeline dashboard — including baby size comparisons, milestone tracking, and a due date probability window.

How Pregnancy Weeks Are Calculated

Pregnancy is measured in gestational weeks, counting from the first day of your last menstrual period (LMP), not from conception. This means:

  • Week 1–2: You are not pregnant yet — this is your menstrual and follicular phase.
  • Week 3: Ovulation and conception typically occur.
  • Week 4: Implantation happens. You may miss your next period.
  • Week 5–40: Fetal development and growth.

If you know your conception date, the due date is approximately 38 weeks (266 days) later. The LMP method adds 2 weeks to account for the pre-ovulation phase.

Frequently Asked Questions

How many weeks pregnant am I?
Enter your due date, LMP, or conception date into our calculator and it will instantly tell you your current pregnancy week and day. Pregnancy is measured from the first day of your last period, so if you're 6 weeks pregnant, conception happened about 4 weeks ago.
How many months pregnant am I?
12 weeks = 3 months, 20 weeks = 5 months, 32 weeks = 8 months. Since months vary in length and pregnancy is tracked in weeks, the conversion is approximate. Our Weeks to Months table gives you the full breakdown.
Why does my app and ultrasound show different weeks?
It's very common for dates to differ. The LMP method assumes ovulation on day 14 of a 28-day cycle, but many women ovulate later or earlier. Ultrasound measures fetal size, which can vary. Doctors typically rely on first-trimester ultrasound for the most accurate dating. A difference of 5-7 days is normal.
What are the trimesters of pregnancy?
First trimester: weeks 1-13. Second trimester: weeks 14-27. Third trimester: weeks 28-40. Each trimester marks different developmental milestones and prenatal care schedules.
How accurate is my due date?
Fewer than 4% of babies arrive on their exact due date. About 60% are born within a week of their due date, and nearly 90% within two weeks. A full-term pregnancy ranges from 37 to 42 weeks. Think of your due date as the center of a 4-week window. Use our Due Date Probability Window to see your most likely delivery range.

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Your Pregnancy Timeline at a Glance

This pregnancy due date calculator gives you more than just a date — it's a complete pregnancy dashboard. Track your progress week by week, see your baby's size, understand key milestones, and plan ahead with confidence. Bookmark this page and return throughout your pregnancy to stay informed at every stage.