Pregnancy Week Calculator
Calculate how far along you are today, compare your medical age to approximate fetal age, and explore common weekly baby and body milestones.
Calculation Method
Select the dating method you want to use.
Calculate your week
Enter your dating information above to generate your customized pregnancy week dashboard.
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Pregnant
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40-Week Mark
This Week's Milestones
Week 0Baby Insight
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Body Insight
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Normal ranges, not a checklist. Every pregnancy is unique.
Age Discrepancy Map
Why is the fetal age lower? Medical counting (gestational age) starts from your last period because it is a known date. Approximate fetal age starts about 2 weeks later at conception. Both timelines describe the same pregnancy from different starting points.
Biological Reality
How doctors count pregnancy weeks
The medical counting system can feel like "fake math" at first, but there is a very practical clinical reason it is used globally.
Week count starts from LMP
This is the standard medical method because the first day of the last period is a tangible bleeding event that is usually easy to identify and record.
Conception happens at 'Week 2'
Because counting starts at LMP, you are officially considered '2 weeks pregnant' on the day you actually conceive. This is completely normal.
Ultrasound overrides calendar math
If an early ultrasound shows the fetus measuring differently than the LMP timeline suggests, the clinical estimate will be updated. Always use the ultrasound date.
FAQ
Pregnancy Week Questions
1Why does the doctor say I'm further along than I expected?+
This is a very common early-pregnancy confusion. Doctors count pregnancy weeks from the first day of your last menstrual period (LMP), not from the day you conceived. That means you are often considered about 2 weeks pregnant when conception actually happens.
2Why do doctors use my last period instead of my conception date?+
The exact moment of ovulation and conception is invisible and hard to prove, even for women who track their cycles. A menstrual period is a definitive, observable bleeding event, making it the most reliable universal starting line for medical dating.
3What is the difference between Gestational Age and Fetal Age?+
Gestational Age is the medical standard, counting from your Last Menstrual Period (LMP). Fetal Age is the actual biological age of the developing baby, which starts roughly 2 weeks later at conception. If your Gestational Age is 8 weeks, the Fetal Age is only 6 weeks.
4Should I calculate by my last period or my ultrasound due date?+
If you have already had a first-trimester ultrasound and your doctor gave you an official due date, use that official due date. Ultrasound dating is usually more accurate than calendar-only estimates, especially early in pregnancy.
5Do all pregnancy symptoms happen at the exact week listed?+
No. Weekly milestones are based on general clinical averages. Every woman's body reacts to pregnancy hormones differently. Experiencing symptoms earlier, later, or not at all is very common and usually completely normal.
Next step
Deepen your understanding
If you want to understand exactly how due dates are established or why clinical dating may change your timeline, read our guides.