PregnancyCalc.comPregnancy Calculators
How Many Weeks Pregnant
Gestational Age Calculator
Calculate how many weeks and days pregnant you are from your last menstrual period. Get your estimated due date instantly.
Weeks + days
Due date
Trimester
Gestational Age Calculator — How Far Along Are You?
Enter the first day of your last menstrual period (LMP). Gestational age is calculated from this date.
⚠ This calculator uses ACOG (American College of Obstetricians and Gynecologists) guidelines. Always follow your healthcare provider’s advice for your specific pregnancy.
Use the first day of your last period
Gestational Age
— weeks
Weeks and days pregnant
Estimated Due Date
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Based on 40-week cycle
Trimester
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Current stage
Pregnancy Milestones
1st Trimester
Weeks 1-12
Organ development
2nd Trimester
Weeks 13-26
Growth phase
3rd Trimester
Weeks 27-40
Final growth
Weeks Remaining
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Gestational Age Calculator — Key Information
How It WorksGestational age is counted from the first day of your last period, not conception.
Due Date MethodAdd 280 days (40 weeks) to the first day of your last period.
AccuracyOnly accurate with regular 28-day cycles. An early ultrasound gives the most accurate date.
Trimesters1st: weeks 1-12. 2nd: weeks 13-26. 3rd: weeks 27-40.
Full TermA full-term pregnancy is 39-40 weeks. 37-38 weeks is early term.
Ultrasound DatesIf ultrasound differs by more than 7-10 days, your provider may adjust your due date.