Pregnancy Week Calculator
Find out exactly how many weeks and days pregnant you are, with a progress bar and development milestones.
About this calculator
Enter your last menstrual period or estimated conception date to see exactly how far along you are — in weeks and days — along with which trimester you're in and a visual progress bar toward the standard 40-week mark. General development milestones for your current stage are shown for context; every pregnancy progresses differently.
Frequently asked questions
- Why does pregnancy last 40 weeks if it's only 9 months?
- 40 weeks works out to roughly 9.2 months, and — importantly — that count starts from your last menstrual period, about two weeks before conception actually occurs. So a pregnancy is really about 38 weeks from conception, but 40 weeks is the standard way it's measured and discussed.
- What's the difference between LMP-based and conception-based dating?
- LMP-based dating (the medical standard) starts counting from your last period. Conception-based dating starts about 2 weeks later, from the estimated day of conception. This calculator supports either as a starting point and converts appropriately.
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🔒 All calculations run entirely in your browser — nothing you enter is ever sent anywhere. These are estimates based on standard averages, not medical advice — consult your healthcare provider for guidance specific to you.