Second Trimester Start Calculator

About this calculator

Pregnancy is conventionally divided into three trimesters, and clinicians commonly mark the start of the second trimester at 14 weeks (98 days) from the first day of the last menstrual period — the same LMP-based dating convention used for due-date estimates like Naegele's rule.

The second trimester is often called the most comfortable stretch of pregnancy, as early symptoms like nausea typically ease and it's when anatomy scans and other routine second-trimester screenings are scheduled. Expectant parents and prenatal care providers use this milestone to plan checkups, screening windows, and simply to track where a pregnancy stands.