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Pregnancy Trimester Calculator
Find current trimester and key milestone dates (end of trimester 1 at 13w 6d, trimester 2 at 27w 6d, full term at 39w-40w).
HEALTHFind current trimester and key milestone dates (end of trimester 1 at 13w 6d, trimester 2 at 27w 6d, full term at 39w-40w).
Detailed instructions, formula notes, and US-context guidance shown in the calculator above.
Disclaimer: Estimate only. Consult a qualified professional for decisions with major financial, legal, or health consequences.
Pregnancy Trimester Calculator
Find current trimester, weeks gestation, and key milestone dates. Trimester boundaries: T1 ends 13w 6d, T2 ends 27w 6d, full term at 39w-40w.
2nd Trimester
15w 3d
Due date (EDD)November 8, 2026
End of T1 (13w 6d)May 9, 2026
End of T2 (27w 6d)Aug 15, 2026
Calculated by Naegele's rule (LMP + 280 days). Ultrasound dating in T1 is more accurate. Trimester definitions vary slightly between OB/GYN, ACOG, and patient-facing resources.
Frequently Asked Questions
What is the Pregnancy Trimester Calculator for?
Find current trimester and key milestone dates (end of trimester 1 at 13w 6d, trimester 2 at 27w 6d, full term at 39w-40w).
How do I use the Pregnancy Trimester Calculator?
Detailed instructions, formula notes, and US-context guidance shown in the calculator above.
How accurate are my pregnancy trimester results?
Estimate only. Consult a qualified professional for decisions with major financial, legal, or health consequences.
Is the Pregnancy Trimester Calculator free to use?
Yes - every calculator on WhichCalc is completely free with no signup, no usage limits, and no tracking on the calculation itself. Results display instantly in your browser and your inputs are never sent to a server. Bookmark the page if you use this calculator regularly.