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Pregnancy Due Date Calculator

Estimate your due date and see how far along you are, with key pregnancy milestones.

Runs locally — files never leave your device

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How to use Pregnancy Due Date Calculator

  1. 1Choose how to calculate — from the first day of your last period, the conception date, an IVF transfer date or an ultrasound scan.
  2. 2Enter the date. For the last-period method, adjust your usual cycle length if it isn't 28 days.
  3. 3For an ultrasound, enter the gestational age measured at the scan in weeks and days.
  4. 4Read your estimated due date, how many weeks and days pregnant you are, your trimester and upcoming milestones.

When is my baby due?

Finding out you're pregnant raises one question straight away: when will the baby arrive? This due date calculator estimates it from the information you have — the first day of your last period, the date of conception, an IVF embryo transfer or an ultrasound scan. It also tells you how many weeks and days pregnant you are today, which trimester you're in and when important milestones fall.

Features

  • Five methods: last period, conception date, 3-day or 5-day IVF transfer, and ultrasound dating.
  • Cycle-length adjustment for periods that are longer or shorter than 28 days.
  • Weeks pregnant today, trimester and days remaining.
  • Milestone dates: end of each trimester, anatomy scan, full term and due date.
  • Private: no sign-up, nothing stored.

Pregnancy timeline

Weeks Stage
0–2 Counted from the last period; ovulation and conception around week 2
4–5 A home pregnancy test usually turns positive
6–8 Heartbeat often visible on an early ultrasound
13 weeks 6 days End of the first trimester
18–22 Anatomy (anomaly) scan
27 weeks 6 days End of the second trimester
37–38 Early term
39–40 Full term; the due date is at 40 weeks
41–42 Late term; your care provider will discuss next steps

Important

Every pregnancy is different. This tool uses standard obstetric formulas to give an estimate and doesn't replace medical care. Your doctor or midwife may set a different due date based on your scans, and that date is the one to follow.

Related tools

Count the days between any two dates with the Date Difference Calculator, or work out a baby's exact age later with the Age Calculator.

Frequently asked questions

How is the due date calculated?
Pregnancy is counted from the first day of the last menstrual period (LMP), and the due date is 280 days — 40 weeks — later. This is Naegele's rule. For cycles longer or shorter than 28 days, the date is shifted by the difference, because ovulation usually happens about 14 days before the next period.
How accurate is a due date?
It's an estimate. Only about 4–5% of babies are born on their due date; most arrive within two weeks either side. An early ultrasound measurement (before about 14 weeks) is usually the most accurate way to date a pregnancy, and your care provider may adjust your due date after it.
Why am I "2 weeks pregnant" at conception?
Gestational age is counted from the last period, about two weeks before conception happens. So at the moment of conception you are considered roughly 2 weeks pregnant, even though the embryo is just forming.
How is the date calculated for IVF?
After a 3-day embryo transfer the pregnancy is counted as 2 weeks and 3 days along on the transfer day; after a 5-day (blastocyst) transfer, 2 weeks and 5 days. The due date is then 263 or 261 days after the transfer date respectively.
Are my dates stored?
No. The calculation happens in your browser, and nothing you enter is saved or sent anywhere.

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