How can I calculate my pregnancy week?
Pregnancy weeks are commonly counted from the first day of the last menstrual period (LMP), rather than from the conception date.
Calculation: completed weeks = days since the LMP ÷ 7. A conventional estimated due date is 280 days, or 40 weeks, after the LMP.
Example: 70 days after the LMP corresponds to 10 completed weeks.
This result is an estimate. Cycle length, ultrasound findings and clinical circumstances can change dating; consult a qualified healthcare professional for medical guidance.
Inputs are processed in your browser and are not sent to our server.