Pregnancy Week Calculator
Calculate Pregnancy Week
Find out how far along you are
Formula
Pregnancy Week = (Today - LMP) / 7 | Due Date = LMP + 280 days | Trimester: 1st (1-12wk), 2nd (13-27wk), 3rd (28-40wk)
Frequently Asked Questions
How do you count pregnancy weeks?
Pregnancy is counted from the first day of your last menstrual period (LMP), not from conception. This means you are about 2 weeks 'pregnant' before conception actually occurs. Full term pregnancy is 40 weeks from LMP.
What are the three trimesters?
First trimester: weeks 1-12 (major organ development). Second trimester: weeks 13-27 (rapid growth, movement felt). Third trimester: weeks 28-40 (brain development, weight gain, preparation for birth).
When is my due date?
Your estimated due date is 280 days (40 weeks) from the first day of your last menstrual period. Only about 5% of babies are born on their exact due date. Most are born within 2 weeks before or after.
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