Calculate your estimated due date using last menstrual period, conception date, or IVF transfer date. See gestational age, trimester, and key pregnancy milestones.
A pregnancy due date calculator estimates when a baby is likely to be born, based on the first day of the last menstrual period, the conception date, or an IVF transfer date. It also shows the current gestational age, trimester, and key developmental milestones throughout the pregnancy.
June 1, 2027
Estimated Due Date
266
Days Until Due Date
Last updated:
Due Date
The estimated due date (EDD) is calculated using Naegele's rule: the first day of the last menstrual period (LMP) + 280 days (40 weeks). This is the standard method used by obstetricians worldwide and is based on average human gestational length.
It is important to understand that only about 5% of babies are born on their calculated due date. The normal range is 37β42 gestational weeks. Birth before 37 weeks is considered premature, while after 42 weeks is post-term.
Methods
By Last Menstrual Period (LMP): The most common method. You need the exact date of your last period. If your cycle is not 28 days, the calculator adjusts automatically to account for your actual cycle length.
By Conception Date: If you know the exact date of conception (e.g., through ovulation monitoring), use this method. Due date = conception date + 266 days.
By IVF Transfer: For a 5-day blastocyst transfer, the due date = transfer date + 261 days. This accounts for the 5 days of in-vitro development before transfer.
Trimesters
First Trimester (Weeks 1β13): All major organs begin forming. The risk of miscarriage is highest during this period. Typical symptoms include nausea, fatigue, and breast tenderness.
Second Trimester (Weeks 14β27): Most symptoms ease. Around week 20, an anatomy scan checks fetal development. Mothers typically begin feeling fetal movement around weeks 16β20.
Third Trimester (Weeks 28β40): The baby rapidly gains weight and prepares for birth. At week 36 the baby is considered full term. Common discomforts include back pain and Braxton Hicks contractions.
Ultrasounds
11β14 week scan β nuchal translucency
Measures nuchal fold thickness to assess chromosomal anomaly risk.
20 week anatomy scan
Examines all major organs and can reveal the baby's sex.
Regular prenatal monitoring
Consistent prenatal care is essential for a healthy pregnancy outcome.
First-trimester blood tests
Combined with the nuchal scan, blood markers help assess risk for Down syndrome and other conditions.
Third-trimester growth scan
Around week 32β36, checks fetal growth, position, and amniotic fluid levels.
Kick counting from week 28
Track at least 10 movements in 2 hours daily. Report any significant decrease to your doctor immediately.
The most common method uses Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). If your cycle is not 28 days, the calculator automatically adjusts for your actual cycle length.
Only about 5% of babies are born on their calculated due date. A normal pregnancy ranges from 37 to 42 weeks. The due date is a statistical midpoint, not a precise prediction.
Gestational age is the number of weeks and days since the first day of your last menstrual period. At conception, gestational age is typically 2 weeks. A full-term pregnancy is between 37 and 42 weeks.
For a 5-day blastocyst transfer, enter your transfer date and the calculator adds 261 days. This accounts for the 5 days of in-vitro development before the embryo was transferred.
The first trimester covers weeks 1β13, the second trimester weeks 14β27, and the third trimester weeks 28β40. Most major organ development occurs in the first trimester, and the baby gains the most weight in the third.