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Pregnancy Calculator Due Date Gestational Age in Weeks & Months

Calculate your due date, gestational age, and track your pregnancy journey with our comprehensive calculator

Free Calculator Instant Results Week by Week Month by Month
Pregnancy Calculator showing fetal development stages from conception to full term with gestational timeline
✨ Visual Guide
Interactive pregnancy timeline showing fetal development from weeks 1-40

Pregnancy Calculator: Due Date & Gestational Age

Core Idea: This calculator estimates your due date, gestational age in weeks and months, and trimester based on last period, conception, due date, ultrasound, or IVF transfer. It helps you track your pregnancy timeline and milestones.
How It Works: Enter your information (LMP, conception, due date, ultrasound, or IVF). The tool uses standard formulas: due date = LMP + 280 days; gestational age = today - LMP; trimesters: 1st (0-13w), 2nd (14-27w), 3rd (28-40w).
Sanity Checks: If your due date is far from 40 weeks after LMP, double-check your input. For IVF, select the correct embryo age. For ultrasound, use the gestational age at scan.
Shortcuts: Most pregnancies last 40 weeks from LMP. If you know your due date, you can back-calculate LMP. IVF day 5 transfer: add 261 days to transfer date for due date.
Pitfalls: Irregular cycles may shift due date. Ultrasound is more accurate if LMP is uncertain. IVF due dates depend on embryo age. Always consult your doctor for medical advice.
Micro-examples: LMP 1 Dec 2024 → Due date 7 Sep 2025. IVF day 5 transfer 1 Jan 2025 → Due date 19 Sep 2025. Ultrasound at 8w0d on 1 Feb 2025 → LMP 8 Dec 2024.
Mini-FAQ:
  • How accurate is this? Accurate for most, but see your doctor for confirmation.
  • Can I use conception date? Yes, it adds 266 days to conception date.
  • What if I have twins? This tool assumes singleton pregnancy.
Action Tip: Bookmark this page to track your pregnancy week by week and share your timeline with your healthcare provider.

How to Calculate Due Date and Gestational Age

Our pregnancy calculator offers multiple calculation methods to determine your due date and gestational age:

Understanding Gestational Age in Weeks & Months

Gestational age is measured from the first day of your last menstrual period, not from conception. Our calculator displays both:

Detailed Pregnancy Timeline Table

Our enhanced pregnancy calculator includes a comprehensive table showing:

👶 Visual Pregnancy Development Timeline

As shown in our pregnancy calculator illustration above, fetal development progresses through distinct stages from conception to full term. Each week brings remarkable changes in your baby's growth and development.

First Trimester (1-12 weeks)
Major organ development, heartbeat detection, basic body structure formation
Second Trimester (13-27 weeks)
Rapid growth, movement detection, gender determination, brain development
Third Trimester (28-40 weeks)
Weight gain, lung maturation, positioning for birth, final preparations

Why Our Pregnancy Calculator is the Best Choice

Understanding Your Pregnancy Results

When you use our pregnancy calculator, you'll receive:

Pregnancy Stages and Milestones

Track your pregnancy journey with our detailed milestone calendar:

Use our pregnancy calculator due date gestational age in weeks & months to stay informed about your pregnancy timeline and never miss important milestones. Get accurate, instant results and plan your pregnancy journey with confidence!

Frequently Asked Questions

How accurate is the pregnancy calculator?

Our pregnancy calculator is highly accurate, using medical-standard calculations. The LMP method has a margin of ±7 days, while ultrasound dating is typically accurate within 3-5 days during the first trimester.

What if I have irregular periods?

If you have irregular periods, the conception date or ultrasound dating methods will provide more accurate results than the LMP method. Consult your healthcare provider for the most precise dating.

Can I use this calculator for IVF pregnancies?

Yes! Our calculator includes specific options for IVF pregnancies. Use the conception date method with your embryo transfer date, accounting for the embryo's age at transfer (3 or 5 days).

How is gestational age different from fetal age?

Gestational age is calculated from your last menstrual period and is about 2 weeks longer than fetal age (which starts from conception). Medical professionals typically use gestational age for consistency.