What is gestational age?+
Gestational age is the measure doctors and midwives use to track how far along a pregnancy is. It is counted from the first day of the last menstrual period (LMP), not from the date of conception. This is the international medical standard because ovulation and conception are harder to determine precisely.
How is gestational age calculated?+
Gestational age is calculated by counting the days from the first day of the last menstrual period to today, then converting to weeks and days. For example, if 70 days have passed since the LMP, the gestational age is exactly 10 weeks. Our calculator performs this calculation automatically.
How many weeks does a normal pregnancy last?+
A full-term pregnancy lasts approximately 40 weeks (280 days) counted from the LMP, although it is normal for birth to occur between weeks 37 and 42. A pregnancy is considered full term starting at 37 weeks.
What are the trimesters of pregnancy?+
Pregnancy is divided into three trimesters: the first from weeks 1 to 13, the second from weeks 14 to 27, and the third from week 28 until birth. Each trimester has specific fetal development characteristics and recommended medical checkups.
When is the first ultrasound performed?+
The first dating ultrasound is usually performed between weeks 6 and 12 of pregnancy. Its main purpose is to confirm gestational age, verify the fetal heartbeat, and rule out multiple pregnancies. Ultrasound is the most accurate method for determining gestational age.
What is the Estimated Due Date (EDD)?+
The Estimated Due Date (EDD) is the date when birth is expected to occur. It is calculated by adding 280 days to the first day of the last menstrual period. It can also be obtained using Naegele's rule: subtract 3 months and add 7 days to the LMP date. Only about 5% of babies are born exactly on the EDD.
How do I calculate my due date if I don't remember my last period?+
If you don't remember the date of your last menstrual period, you can use the estimated conception date (usually around 14 days after the LMP) or the due date already determined by your doctor via ultrasound. Our calculator accepts all three input methods.
Is it normal for a baby to be born before or after the due date?+
Yes, completely normal. Only about 5% of babies are born exactly on the estimated due date. Most babies are born within two weeks before or after the EDD. A birth before week 37 is considered premature, and after week 42 is post-term.
What is the difference between gestational age and fetal age?+
Gestational age is counted from the last menstrual period (LMP) and is what doctors use. Fetal age (or conceptional age) is counted from the date of conception, usually about 2 weeks less than gestational age. When your doctor says you are 10 weeks pregnant, they mean 10 weeks gestational age.
Does this gestational age calculator replace medical advice?+
No. This calculator is a reference tool for informational purposes only. Accurate gestational age determination must always be performed by a healthcare professional, ideally through obstetric ultrasound. The results of this tool do not substitute professional medical diagnosis or advice.