About the Due Date Calculator
Estimate your baby’s due date using the method that matches what you know: last menstrual period, conception date or IVF embryo transfer date. You will also see when each trimester begins.
How to use it
- Choose a calculation method.
- Enter the date (and cycle length or embryo age if asked).
- See your due date and trimester dates.
Formula & method
LMP: due = LMP + 280 days (+ cycle − 28)
Conception: due = conception + 266 days
IVF: due = transfer + 266 − embryo age (days)Frequently asked questions
How many babies arrive on their due date?
Only about 4–5%. Most babies are born within two weeks either side of the estimated due date.
Results are estimates for general information only and are not financial, tax, legal or medical advice. Please confirm important decisions with a qualified professional.