Calculate gestational age in weeks and days from your LMP. Track your pregnancy progress with exact gestational age and milestones.
Gestational age (GA) is the standard measurement used by healthcare providers to describe how far along a pregnancy has progressed. Measured from the first day of the last menstrual period rather than from conception, gestational age includes approximately two weeks before the embryo was actually conceived.
This calculator provides your exact gestational age in weeks and days, which is the format used on ultrasound reports, in medical records, and in pregnancy guides. It also converts the same data into total days, shows fetal age (age since conception), and identifies developmental milestones appropriate for your current GA.
Accurate gestational age is crucial because it determines the timing of prenatal screenings, the interpretation of ultrasound measurements, and the assessment of fetal growth. It also defines when a pregnancy is considered preterm, full-term, or post-term. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation.
Healthcare providers use gestational age to guide every aspect of prenatal care. Knowing your exact GA ensures you never miss a time-sensitive screening, helps you understand fetal development updates, and gives you and your provider a common reference point for tracking pregnancy progress. Having a precise figure at your fingertips empowers better planning and more confident decisions.
GA (days) = today − LMP GA (weeks) = floor(GA_days / 7) GA (remaining days) = GA_days mod 7 Fetal Age = GA − 14 days (approximate)
Result: 10 weeks, 1 day
If your LMP was December 1, 2025, and today is February 9, 2026, the gestational age is 71 days, or 10 weeks and 1 day. Fetal age (from estimated conception) is approximately 8 weeks and 1 day. At this GA, the embryo is about 3 cm long and all major organs are forming.
Gestational age is written as weeks + days, such as 10w3d (10 weeks and 3 days). The week number starts from 0 at LMP and progresses to 40 at the due date. You are "in your 11th week" when your GA reads 10w0d through 10w6d.
Many critical pregnancy tests have narrow GA windows. The nuchal translucency scan must be done between 11w0d and 13w6d. The quad screen is drawn between 15w0d and 22w6d. The glucose challenge test is typically at 24w0d to 28w0d. Knowing your exact GA ensures these tests happen at the right time.
ACOG defines delivery categories by GA: preterm (<37w), early term (37w-38w6d), full term (39w-40w6d), late term (41w-41w6d), and post-term (≥42w). Elective delivery before 39 weeks is generally discouraged unless medically indicated.
Gestational age (GA) counts from the first day of your LMP and includes about 2 weeks before conception. Fetal age counts from the actual date of conception. A pregnancy at 10 weeks GA has a fetus that is approximately 8 weeks old.
Because the LMP is a known, datable event for most women, while the exact moment of conception is rarely known. Using the LMP provides a consistent starting point. This convention has been standard for over a century.
Key milestones include: heartbeat visible at 6-7 weeks, all organs forming by 8 weeks, end of first trimester at 12 weeks, quickening at 16-22 weeks, viability at 24 weeks, and full term at 39 weeks. Knowing these milestones helps you track your baby's development and understand the timing of important prenatal screenings.
Not exactly. 40 weeks is 280 days, which is about 9 months and 7 days. The discrepancy arises because calendar months vary in length from 28 to 31 days, while pregnancy is measured in fixed 7-day weeks.
Yes. The New Ballard Score assesses a newborn's physical and neuromuscular maturity to estimate gestational age at birth. This is useful when prenatal dating is uncertain.
EGA stands for Estimated Gestational Age. It is the same as GA but emphasizes that it is an estimate. You may also see EDC (Estimated Date of Confinement), which is an older term for EDD.