Pregnancy Calculator

Category: Pregnancy
- April 01, 2025
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Calculate important pregnancy dates and milestones based on your last menstrual period (LMP) or due date. Track trimesters, development stages, and get personalized week-by-week information.

Calculate Due Date

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Additional Information (Optional)

Medical Disclaimer

This calculator provides estimates based on standard pregnancy calculations. Every pregnancy is unique, and dates may vary. This tool should not replace professional medical advice. Always consult with your healthcare provider for personalized guidance about your pregnancy.

About Pregnancy Due Date Calculation

A typical pregnancy lasts about 40 weeks (280 days) from the first day of the last menstrual period. The due date is an estimate, as only about 5% of babies are born on their exact due date.

Naegele's rule is the standard method for calculating the estimated due date (EDD). It involves adding 1 year, subtracting 3 months, and adding 7 days to the first day of the last menstrual period. This calculator uses this method with adjustments for cycle length when calculating from LMP.

Pregnancy Calculator Overview

This Pregnancy Calculator helps you estimate important milestones in your pregnancy journey. Whether you're calculating your due date, tracking your pregnancy week by week, or estimating your conception date, this tool simplifies the process. It's useful for early pregnancy planning, understanding fetal development stages, and keeping up with key prenatal appointments.

Formula Used

Naegele’s Rule:
Due Date = First Day of Last Menstrual Period + 1 year − 3 months + 7 days

Adjusted for Cycle Length:
Due Date = LMP + 280 days + (Cycle Length − 28 days)

From Conception Date:
Due Date = Conception Date + 266 days

From IVF Transfer:
Due Date = Transfer Date + (267 − Embryo Age in Days)

How to Use the Pregnancy Calculator

The calculator offers four methods to determine your estimated due date and track your pregnancy:

  • Last Menstrual Period: Enter the first day of your last period and your average cycle length.
  • Conception Date: Input the date of conception or IVF transfer. You can also specify embryo age for IVF cases.
  • Due Date: If your healthcare provider has already given you an expected delivery date, you can use it directly.
  • Ultrasound Date: Use your ultrasound scan date and the gestational age determined at that time.

After entering your information, click “Calculate” to see your full pregnancy timeline. You'll get an overview of your current week, trimester, estimated conception date, and more.

What You'll Learn

This tool provides helpful information such as:

  • Your expected delivery date (EDD)
  • Your current week and day of pregnancy
  • Which trimester you're in
  • Important medical milestones like viability, ultrasounds, and tests
  • Weekly baby development updates and changes in your body

Why Use This Calculator?

This pregnancy week calculator supports your journey from early conception to birth. It complements other tools like:

Together, these tools can act as a complete pregnancy planning aid and fertility calendar.

Frequently Asked Questions (FAQ)

How accurate is the due date?

The due date is an estimate. Most pregnancies last about 40 weeks, but babies can arrive a few weeks before or after. Only about 5% are born exactly on their due date.

Can I use this if I had IVF?

Yes. You can enter your IVF transfer date and embryo age for a more accurate estimate.

What if I don’t know my LMP?

You can use the conception date, due date, or ultrasound method instead. All options give reliable estimates.

Does this replace medical advice?

No. This tool gives helpful estimates and guidance, but always consult your healthcare provider for medical care and prenatal planning.

How often should I update the calculator?

You can use it once or revisit weekly to check your progress and see new baby development info.

Final Thoughts

The Pregnancy Calculator is a practical way to track your pregnancy timeline, predict your baby’s arrival, and plan key steps along the way. It’s easy to use and integrates well with other tools like ovulation trackers and period calculators to support your reproductive health.