Pregnancy Week Calculator

Find out your current pregnancy week, trimester, and key milestones for this stage of development.

Results

Visualization

How It Works

Pregnancy is divided into three trimesters. Each week brings new developmental milestones for your baby. This calculator shows where you are and what is happening. Not medical advice.

The Formula

Weeks = Days since LMP / 7
Trimester: 1-12 = First, 13-26 = Second, 27-40 = Third

Variables

  • LMP — First day of last menstrual period
  • Trimester — One of three pregnancy stages

Example

84 days since LMP = 12 weeks exactly, end of first trimester, baby is lime-sized.

Tips

  • Each trimester brings different symptoms and checkups
  • The second trimester (weeks 13-26) is often called the "honeymoon" period
  • Third trimester visits become more frequent -- weekly after week 36
  • Preterm is before 37 weeks; full term is 39-40 weeks

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