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Pregnancy Due Date Calculator — Free EDD Calculator (LMP, IVF & Ultrasound)

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Pregnancy Due Date Calculator — Free EDD Calculator | Enavec Pharmacy
🤰 Free · Accurate · Global · No Sign-up

When Will Your
Baby Arrive?

Calculate your estimated due date in seconds. Three calculation methods, full trimester breakdown, weekly milestones, and a personalised pregnancy checklist.

Naegele's Rule formula IVF transfer supported 100% private Works globally

Choose Your Calculation Method

Select the method that matches the information you have available.

Day 1 of your most recent menstrual period
28 days
Affects ovulation timing. Average is 28 days.
Note: Enter the date you believe conception occurred — typically your ovulation day. Your due date is calculated by adding 266 days (38 weeks) to this date.
The day you ovulated or believe conception occurred
IVF Due Date: Day 5 blastocyst transfer adds 261 days. Day 3 embryo transfer adds 263 days. These are calculated from the transfer date itself.
The date of your embryo transfer procedure
Provided by your fertility clinic
Ultrasound Dating: Enter the date of your scan and the gestational age your sonographer reported. This is often the most accurate method, especially if done before 14 weeks.
The date the scan was performed
The weeks pregnant reported by the sonographer

Your Pregnancy Results

Estimated Due Date

—
—
Days Remaining
📅
Gestational Age
—
👶
Fetal Age
—
From conception
🌱
Current Trimester
—
🔢
Conception Window
—
Estimated conception date
🗓️
Viability Reached
—
Week 24 milestone

Trimester Timeline

Your pregnancy divided into its three phases — with progress based on today's date

Pregnancy Milestones

Key developmental and medical milestones throughout your pregnancy

Your Trimester Checklist

Personalised tasks based on where you are in your pregnancy

Save your pregnancy calendar

Frequently Asked Questions

Everything you need to know about pregnancy due dates

The most common method is Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14. Your due date can also be calculated from conception date (add 266 days) or from an ultrasound scan, which measures the baby's size to estimate gestational age.
A due date calculator gives an estimated due date (EDD), not a guaranteed birth date. Only about 5% of babies are born on their exact due date. Most babies arrive within 2 weeks before or after the EDD. An early ultrasound scan (before 14 weeks) gives the most accurate dating. If your cycle is irregular, a calculator based on LMP may be less accurate.
The first trimester runs from week 1 to week 13 and covers early development, when all major organs begin forming. The second trimester spans weeks 14 to 27, when the baby grows rapidly, movements are felt, and most anomaly scans are done. The third trimester covers weeks 28 to 40+, when the baby gains weight, the lungs mature, and the body prepares for birth.
Gestational age is counted from the first day of your last menstrual period and is the standard used by healthcare providers — a full-term pregnancy is 40 gestational weeks. Fetal age (or embryonic age) counts from the moment of conception, which typically occurs around day 14 of the cycle, making it approximately 2 weeks less than gestational age.
Your first antenatal (booking) appointment should ideally take place between 8 and 12 weeks of pregnancy. At this appointment, your healthcare provider will confirm the pregnancy, take your medical history, offer blood tests, and schedule your first ultrasound (dating scan), typically between 11 and 14 weeks.
A pregnancy is considered post-term at 42 weeks. Between 40 and 42 weeks, your healthcare provider will monitor you and the baby closely. Most providers discuss induction of labour around 41–42 weeks. Going a few days past your due date is common — only about 5% of babies arrive on their exact EDD.
For IVF pregnancies, the due date is calculated from the egg retrieval or embryo transfer date. For a Day 3 embryo transfer, add 263 days. For a Day 5 blastocyst transfer (the most common), add 261 days. These calculations are generally more precise than LMP-based methods because the date of fertilisation is known exactly.

Understanding Your Pregnancy Due Date

Your estimated due date (EDD) is one of the most important pieces of information in your pregnancy. It guides your antenatal care schedule, helps your healthcare provider monitor your baby's growth and development, and determines when interventions like induction of labour might be considered.

How Naegele's Rule Works

The standard method for calculating a due date is Naegele's Rule, developed by German obstetrician Franz Karl Naegele in the 19th century. The formula adds 280 days — exactly 40 weeks — to the first day of the last menstrual period. This assumes a 28-day cycle with ovulation on day 14. If your cycle is longer or shorter, the due date is adjusted accordingly, which is why entering your accurate cycle length matters.

Why Your Due Date Is an Estimate, Not a Deadline

Research published in the journal Human Reproduction found that only around 4–5% of women give birth on their exact due date. A full-term pregnancy is defined as anywhere between 39 and 40 weeks and 6 days. Early term is 37–38 weeks, late term is 41 weeks, and post-term is 42 weeks or beyond. This means a two-week window around your EDD is entirely normal.

The Role of Ultrasound in Dating

A dating scan performed between 11 and 14 weeks (the first-trimester combined screening) measures the baby's crown-rump length (CRL) — from the top of the head to the base of the spine. This measurement is highly accurate at estimating gestational age, particularly before 14 weeks. If the ultrasound date differs from your LMP-calculated date by more than 7 days, your healthcare provider will typically adjust your due date to match the scan.

Key Antenatal Milestones to Watch For

Early pregnancy brings the booking appointment (8–12 weeks), first-trimester combined screening (11–14 weeks), and the anatomy scan (18–22 weeks) where major structural abnormalities are checked. In the third trimester, growth scans monitor the baby's size, and from 36 weeks your provider will check the baby's position in preparation for birth. Knowing these milestones helps you prepare and ensures you don't miss critical appointments.

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