Due Date Calculator
Find your estimated due date and follow how far along you are, week by week.
This is an estimate to help you plan, not medical advice. Only about 1 in 20 babies arrives on the estimated date. Your provider's dating, often confirmed by ultrasound, takes precedence.
About your due date
How is my due date calculated?
From your last menstrual period, the estimate uses Naegele's rule: 280 days (40 weeks) from the first day of your last period, adjusted if your cycle is longer or shorter than 28 days. From a conception or IVF transfer date, it counts forward from that point instead.
How accurate is an estimated due date?
It is an estimate, not a deadline. Only about 1 in 20 babies is born on the exact due date, and most arrive in the two weeks on either side. An early ultrasound is usually the most accurate dating, so your provider's date takes precedence.
What if I do not know my conception date?
That is completely normal. Most people use the first day of their last period, which is easier to remember. If your cycles are irregular, your provider can confirm dating with an ultrasound.
Your pregnancy week by week
See how your baby is growing, week by week: their size this week, and what is developing.
Sources and further reading
These organizations offer trusted, in-depth guidance. Gentle Apps is independent and not affiliated with them.