A pregnancy week calculator tells you exactly how far along you are in your pregnancy based on your due date or last menstrual period (LMP). Enter a date below to see your current week, trimester, fetal development milestones, and what to expect.
Choose between your due date or last menstrual period (LMP) and enter the date.
View your current gestational age, trimester, and a visual progress bar of your pregnancy journey.
Browse week-by-week fetal development, size comparisons, and common symptoms using the timeline slider.
Pregnancy is calculated from the first day of your last menstrual period (LMP), not from conception. To find your gestational age, count the number of weeks and days from your LMP to today. Alternatively, if you know your due date, subtract it from 280 days (40 weeks) to find your LMP, then count forward to today.
A full-term pregnancy is 40 weeks (280 days) from the first day of your last menstrual period. However, only about 5% of babies arrive on their exact due date. A baby born between 39 and 41 weeks is considered full term.
The first trimester covers weeks 1-12 and is when major organs begin forming. The second trimester spans weeks 13-27, often called the "golden period" as many symptoms ease. The third trimester runs from week 28 to birth, when the baby gains weight rapidly and prepares for delivery.
Viability is generally considered to begin around 24 weeks of gestation. At this point, with intensive medical care, a baby has a chance of survival outside the womb. Survival rates and outcomes continue to improve significantly with each additional week of gestation.
The due date is calculated from the first day of your last menstrual period (LMP), not from conception. Since ovulation typically occurs about 2 weeks after the start of your period, the gestational age is approximately 2 weeks longer than the actual fetal age.
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