Baby Calculator Weeks Pregnant

How to Use This Calculator

Using our pregnancy week calculator is simple:

1. Enter your last menstrual period (LMP) date or your estimated due date (EDD)
2. Select whether you're calculating from LMP or EDD
3. Click "Calculate" to see your current pregnancy week
4. Review the results and development milestones

The calculator will show you:

• Your current pregnancy week
• Estimated due date (if calculating from LMP)
• Key developmental milestones for your baby
• A visual timeline of your pregnancy

Understanding Pregnancy Weeks

Pregnancy is typically divided into three trimesters, each lasting about 13 weeks:

• First trimester (Weeks 1-12): The foundation of your baby's development, including organ formation and early growth
• Second trimester (Weeks 13-26): Rapid growth and development, when many expectant mothers notice changes in their bodies
• Third trimester (Weeks 27-40): Preparation for birth, including fat storage, lung development, and final growth

Fetal Development Stages

Your baby goes through remarkable changes each week. Here are some key developmental milestones:

First Trimester (Weeks 1-12)

• Week 1-2: Implantation and early cell division
• Week 3-4: Heart begins to beat, neural tube forms
• Week 5-6: Limbs begin to form, face develops
• Week 7-8: Major organs are forming, fingers and toes develop
• Week 9-12: Baby can hear sounds, eyes can detect light, rapid growth

Second Trimester (Weeks 13-26)

• Week 13-16: Baby can make facial expressions, moves frequently
• Week 17-20: Hair begins to grow, eyelashes and eyebrows form
• Week 21-24: Baby can hear outside sounds, practice breathing
• Week 25-26: Baby's skin becomes less transparent, nails begin to form

Third Trimester (Weeks 27-40)

• Week 27-30: Baby gains fat for energy, lungs continue to mature
• Week 31-34: Baby's head engages in the pelvis, bones harden
• Week 35-38: Baby is in "active survival mode," practicing breathing
• Week 39-40: Baby is fully developed, ready for birth

How Due Date is Calculated

The due date is calculated by adding 40 weeks (280 days) to the first day of your last menstrual period (LMP).

For example, if your LMP was January 1, 2023, your due date would be October 31, 2023.

Some doctors may use an ultrasound to determine a more precise due date, especially if your LMP is uncertain.

Common Pregnancy Milestones

Here are some common signs that your pregnancy is progressing normally:

First Trimester

• Missed period
• Tender, swollen breasts
• Fatigue and nausea
• Frequent urination
• Food aversions

Second Trimester

• Baby's movements felt by mother
• Nipple tenderness and discharge
• Increased appetite
• Heartburn and acid reflux
• Varicose veins

Third Trimester

• Baby drops into pelvis (engagement)
• Braxton Hicks contractions
• Back pain
• Shortness of breath
• Water breaking