Calculator18 Weeks Pregnant
2nd TrimesterMonth 5Week 18 of 40

18 Weeks Pregnant
— How Many Months Is It?

18w
Equivalent to
Month 5
2nd Trimester
🫑
Baby is the size of a
Bell Pepper
14.2 cm (~5.6 in) · 190g
🌱Fetal Development Milestones — Week 18

Inner ear bones are developed enough that your baby can hear your voice and heartbeat.

Pregnancy timeline progress45%
Week 1Week 18Week 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 18

18 weeks pregnant equals Month 5 of gestation in the 2nd 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.

Inner ear bones are developed enough that your baby can hear your voice and heartbeat.

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).