Pregnancy Due Date Calculator

Calculate your big day and track your pregnancy progress based on your last menstrual period.

Standard is 28 days.
Estimated Due Date
Select Date
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Conception
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2nd Trimester
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3rd Trimester
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How Due Dates are Calculated

While only about 4% of babies are born on their actual due date, having an estimate helps you and your doctor monitor your baby's growth and plan for the big arrival.

  • Naegele's Rule: Most clinicians use this standard formula. It adds 280 days (40 weeks) to the first day of your last menstrual period (LMP).
  • The Cycle Adjustment: If your menstrual cycle is longer or shorter than the "average" 28 days, your ovulation day likely shifted. This calculator adjusts the date by adding or subtracting the difference to give you a more personalized result.
  • Trimester Breakdown:
    • First Trimester: Week 1 through the end of Week 12.
    • Second Trimester: Week 13 through the end of Week 26.
    • Third Trimester: Week 27 until birth.

Medical Disclaimer: This calculator provides estimates based on averages for informational purposes only. Every pregnancy is unique. This tool is not a substitute for professional medical advice, diagnosis, or treatment. Always verify your due date with your OB-GYN or midwife, as they may adjust your date based on early ultrasound measurements.