Pregnancy Week Calculator
Calculate current pregnancy week from last menstrual period
About this calculator
The Pregnancy Week Calculator determines your current pregnancy week based on your last menstrual period (LMP) date. This tool helps expectant mothers track their pregnancy progress, plan prenatal appointments, and understand fetal development milestones. Healthcare providers use the same LMP-based calculation method to establish due dates and monitor pregnancy progression, making this calculator an essential resource for pregnancy planning and monitoring.
How to use
Simply enter the first day of your last menstrual period into the calculator. The tool will automatically calculate how many weeks pregnant you are based on the standard 40-week pregnancy timeline. Results show your current pregnancy week and estimated due date for easy reference.
Frequently asked questions
How accurate is pregnancy week calculation from LMP?
LMP-based calculations are the standard medical method, accurate within 1-2 weeks for women with regular cycles.
What if I don't remember my exact LMP date?
Try to estimate as closely as possible. Your doctor can use ultrasound for more precise dating.
When does pregnancy officially start counting?
Pregnancy weeks are counted from the first day of your last menstrual period, not conception date.