Pregnancy tools
Pregnancy Due Date Calculator
Estimate a due date and current gestational age from the first day of the last menstrual period.
Open due date calculatorQuick answer
This calculator estimates a due date by adding 280 days to the first day of the last menstrual period. A dating scan or clinician may adjust the estimate.
Frequently asked questions
How is a due date estimated?
A common estimate uses 280 days from the first day of the last menstrual period.
Can the due date change?
Yes. Your clinician may use ultrasound dating or other clinical information to revise it.
This tool is for education and does not replace individual medical advice or care.