Enter your LMP date and find out exactly how many weeks and days pregnant you are right now, your trimester, and your due date.
Pregnancy is counted from LMP. Confirm with your OB-GYN and ultrasound.
Pregnancy is measured from the first day of your last menstrual period (LMP), not from conception. This means during "weeks 1–2" you haven't actually conceived yet — ovulation happens around week 2, and conception occurs shortly after. Full-term pregnancy is 40 weeks from LMP.
This is one of the most common sources of pregnancy-week confusion: gestational age (what your doctor uses) is counted from your LMP, while fetal age (actual embryonic development) is counted from conception, roughly 2 weeks later. So when you're "6 weeks pregnant" by gestational age, the embryo itself is closer to 4 weeks of actual development. Both numbers are correct — they're just measuring from different starting points, and it's worth knowing which one any given source is using, especially when comparing week-by-week development guides.
Week-by-week guides describe averages, not universal rules. Some women feel first fetal movement (quickening) as early as 16 weeks, others not until 22-24 weeks, and both are entirely normal, influenced by factors like whether it's a first pregnancy and where the placenta is positioned. Similarly, symptoms like nausea, energy levels, and when the belly "shows" all vary widely between women and even between pregnancies for the same woman. Try to hold week-by-week content as a general guide rather than a strict checklist your own pregnancy needs to match.
The first trimester (weeks 1-13) is when the foundational structures form — the neural tube, heart, and major organs all begin developing in these early weeks, which is exactly why folic acid and avoiding harmful exposures matter so much this early, often before many women even know they're pregnant. The second trimester (weeks 14-27) is typically when growth accelerates, movement becomes noticeable, and the anatomy scan confirms structural development in detail. The third trimester (weeks 28-40) is largely about weight gain, lung maturation, and the baby positioning for birth.
Around 24 weeks is generally considered the threshold of viability outside the womb with intensive medical support, though outcomes improve significantly with each additional week. By 28 weeks, survival rates with NICU support are considerably higher, and by 34-37 weeks, most babies do very well with standard care if born early. These numbers can be reassuring context if you're ever facing a preterm labor scare, though every situation and gestational week carries its own specific considerations your care team will walk you through.
For twin or higher-order pregnancies, week-by-week development follows a similar biological timeline, but full term is defined earlier (around 37 weeks for twins rather than 40), since multiple pregnancies more commonly deliver ahead of a single-baby due date. If you're expecting multiples, your care team will likely set a more individualized monitoring schedule that adjusts standard week-by-week guidance to your specific situation.
Medical Disclaimer: This tool is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for personalized guidance.