First Day of Last Period
Based on the first day of your last menstrual period (LMP), assuming a typical 28-day cycle.
Looking for your due date instead?
Our Pregnancy Due Date Calculator gives you your full clinical screening timeline alongside your estimated due date.
Your results will appear here
Enter the first day of your last period, then click Calculate.
Educational use only. Actual development varies between pregnancies. Your ultrasound-confirmed dates from your care provider are more accurate than LMP-based estimates.