How to use this page
Use LMP dating when you know the first day of your last menstrual period.
BumpCalc guide
Due Date Calculator by LMP
Enter the first day of your last menstrual period to estimate your due date, pregnancy week, trimester, and next milestone.
Live toolUpdates instantly
Estimated due dateFebruary 11, 2027
Current weekWeek 1
TrimesterNot pregnant yet
Pregnancy startMay 7, 2026
Next milestoneYour first prenatal visit is usually the next big planning step.
Helpful next step
Save your estimated date, then compare it with your pregnancy week, trimester, and practical planning timeline.
Trust note
Dates are estimates. Your clinician may adjust them after ultrasound measurements, cycle history, or IVF transfer details.
Quick answers
Common questions
What does LMP mean?
LMP means last menstrual period. Pregnancy dating often starts from the first day of your last period.
How many days are added to LMP?
A common estimate adds 280 days, or 40 weeks, to the first day of your last menstrual period.