1st TrimesterMonth 3Week 13 of 40
13 Weeks Pregnant
— How Many Months Is It?
13w
Equivalent to
Month 3
1st Trimester
🍋
Baby is the size of a
Lemon
7.4 cm (~2.9 in) · 23g
🌱Fetal Development Milestones — Week 13
Vocal cords are forming and unique fingerprints develop on the fingertips.
Pregnancy timeline progress33%
Week 1Week 13Week 40
Calculate Your Exact Due Date
Enter your last period date for an instant gestational calculation
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Enter your date to calculate gestational age.
Based on ACOG guidelines and Naegele's Rule for informational purposes only. Consult your OB-GYN.
Frequently Asked Questions — Week 13
13 weeks pregnant equals Month 3 of gestation in the 1st Trimester. Because calendar months vary between 28 and 31 days while weeks are exactly 7 days, clinical tracking in weeks provides the most accurate timeline.
Vocal cords are forming and unique fingerprints develop on the fingertips.
Use the calculator above: enter the first day of your last period (LMP) and the tool will calculate your exact estimated due date using Naegele\'s Rule (LMP + 280 days).