Pregnancy Week & Due Date Calculator
Enter the first day of your last menstrual period (LMP) to estimate your due date and current gestational week.
Results:
Estimated Due Date:
Current Gestational Age:
Understanding Your Pregnancy Weeks and Due Date
Knowing your estimated due date (EDD) and current gestational age is a crucial part of your pregnancy journey. This calculator uses the most common method, based on the first day of your Last Menstrual Period (LMP), to provide these estimates.
How is the Due Date Calculated? (Naegele's Rule)
The standard method for calculating a due date is called Naegele's Rule. It assumes a 28-day menstrual cycle and that conception occurs around day 14. According to this rule, pregnancy typically lasts about 280 days (40 weeks) from the first day of your LMP.
The formula is simple: LMP Date + 280 days = Estimated Due Date.
For example, if your LMP was January 1, 2024, your estimated due date would be around October 8, 2024.
What is Gestational Age?
Gestational age refers to how far along you are in your pregnancy, measured in weeks and days from the first day of your LMP. This is different from fetal age, which is measured from the actual date of conception (typically about two weeks after LMP).
Healthcare providers use gestational age to monitor the baby's development, schedule prenatal tests, and determine the best time for delivery.
Why is this important?
- Prenatal Care: Helps your doctor track milestones and ensure healthy development.
- Planning: Allows you and your family to prepare for the baby's arrival.
- Medical Decisions: In some cases, knowing the exact gestational age is critical for medical interventions or decisions about delivery.
Limitations and Considerations
While the LMP method is widely used, it has limitations:
- Irregular Cycles: If you have irregular menstrual cycles, your ovulation date might vary significantly, making the LMP method less accurate.
- Unknown LMP: If you don't remember your LMP, this method cannot be used.
- Early Ultrasound: An early ultrasound (typically between 8-12 weeks) can often provide a more accurate due date, especially if there's a discrepancy with the LMP method.
This calculator provides an estimate for informational purposes only. Always consult with your healthcare provider for personalized medical advice and to confirm your due date and gestational age.