Pregnancy week by week tracking helps expectant parents understand fetal development, anticipate common symptoms, and stay on top of important prenatal appointments. Each of the 40 weeks of pregnancy brings distinct changes for both baby and parent — from a cluster of cells to a fully formed newborn ready for the world.
Enter Your Dates
Due date will be calculated as 40 weeks from this date
Key Prenatal Appointments
Full 40-Week Timeline
Medical Disclaimer: This tool is for informational and educational purposes only. The milestones, symptoms, and advice shown are general averages and do not constitute medical advice. Every pregnancy is unique. Always consult your healthcare provider for personalized guidance, diagnosis, and treatment.
How to Use the Pregnancy Week by Week Timeline
Our pregnancy week by week tool transforms your due date or LMP into a complete 40-week visual timeline — showing fetal development, common symptoms, helpful tips, and key prenatal appointments for every week of pregnancy.
Step 1: Choose Your Input Method
You can start from two different dates. If your doctor has already given you an estimated due date — especially one confirmed by an early ultrasound — select "Due Date" and enter it. If you only know when your last menstrual period started, select "Last Period (LMP)" and the tool will calculate your due date as exactly 40 weeks from that date, following the standard gestational age convention used in obstetrics.
Step 2: View Your Current Week
Once you submit your dates, the timeline highlights your current pregnancy week and shows a prominent summary of what is happening right now. You will see your baby's approximate size compared to a familiar fruit or everyday object, key developmental milestones for the week, the most common symptoms experienced at this stage, and practical tips from prenatal guidance experts.
Step 3: Check Key Appointment Dates
The appointments panel shows recommended prenatal visits with estimated calendar dates based on your timeline. These include your first prenatal visit, first-trimester screening, anatomy scan, glucose tolerance test, Group B strep test, and third-trimester weekly check-ins. Use these as a planning guide and confirm timing with your healthcare provider.
Step 4: Explore the Full 40-Week Timeline
Below the current week summary is a complete trimester-by-trimester timeline. Past weeks are shown at reduced opacity; your current week is highlighted with a pink border. Future weeks show what is coming, so you can prepare. Each week card includes the baby's size comparison, a milestone note, typical symptoms, and a tip to keep in mind. Tap or click any week card to expand its details.
Understanding the Three Trimesters
Pregnancy is traditionally divided into three trimesters. The first trimester (weeks 1–13) is a period of rapid early development — organs form, the heartbeat begins, and nausea is common. The second trimester (weeks 14–27) is often called the "golden period" — nausea typically eases, the baby bump becomes visible, and you may feel the first movements. The third trimester (weeks 28–40) is the final growth phase — the baby gains weight rapidly and positions for birth. Your pregnancy timeline shows exactly where you are in each phase.
About Gestational Age vs. Fetal Age
Gestational age — the standard used in this tool and by most healthcare providers — is counted from the first day of your last menstrual period. Actual fertilization typically happens about two weeks later. This is why a pregnancy is said to be 40 weeks long even though conception occurs closer to week 2. When your doctor refers to how many weeks pregnant you are, they are using gestational age.
Frequently Asked Questions
Is this pregnancy week-by-week tool free to use?
Yes, this pregnancy timeline is completely free with no signup, no account, and no hidden fees. Everything runs in your browser — your personal information is never sent to a server.
Is my data private and safe?
Absolutely. All calculations run entirely client-side in your browser. Your due date, LMP, and any other information you enter is never transmitted to any server or stored remotely.
Should I enter my due date or my last menstrual period (LMP)?
You can use either. If you know your due date from an ultrasound or doctor visit, enter it directly. If you know when your last period started, enter your LMP date — the calculator will estimate your due date as 40 weeks (280 days) from that date. Ultrasound-based due dates are typically more accurate.
How accurate are the pregnancy week calculations?
Gestational age in this tool is calculated from your last menstrual period (LMP), which is the standard medical convention. This means week 1 begins on your LMP date even though conception typically happens around week 2. Your doctor may adjust your due date based on early ultrasound measurements.
What happens during the first trimester?
The first trimester covers weeks 1 through 13. During this time, the fertilized egg implants, the embryo's major organ systems begin forming, and the heart starts beating around week 6. This period often brings morning sickness, fatigue, and breast tenderness. Your first prenatal appointment and genetic screening tests typically occur during this trimester.
When does the baby start moving?
Most people feel fetal movement (called quickening) between weeks 18 and 25. First-time parents often notice it later than those who have been pregnant before. Movements typically become stronger and more frequent through the second trimester, and your provider may ask you to track kick counts starting around week 28.
What prenatal appointments should I schedule?
Key appointments include: first prenatal visit (weeks 6-10), nuchal translucency ultrasound (weeks 11-13), anatomy scan (weeks 18-22), glucose screening (weeks 24-28), Group B strep test (weeks 35-37), and weekly visits from week 36 onward. Your healthcare provider will create a personalized schedule based on your health history.
Is this tool a substitute for medical advice?
No. This tool is for informational and educational purposes only. Every pregnancy is different, and the milestones shown are general averages. Always follow the guidance of your healthcare provider for personalized medical advice, diagnosis, and treatment.