Pregnancy Calculator
Calculate your estimated due date and weeks of pregnancy.
Pregnancy calculator: due date and gestational weeks
The pregnancy calculator estimates your due date by adding 280 days from the first day of your last menstrual period. It also shows your current week and trimester.
Each trimester has distinct developmental stages. The first is critical for organ formation, the second for rapid growth, and the third for the baby's final maturation.
Remember that only about 5% of babies are born on their exact due date. This tool is for guidance; always consult your doctor.
Frequently asked questions
How is the due date calculated?
It adds 280 days (40 weeks) from the first day of your last menstrual period. It's an estimate; only about 5% of babies are born on the exact date.
How accurate is the calculator?
It's an estimate based on regular 28-day cycles. Your doctor may adjust the date with ultrasound scans.
Can I use it with irregular cycles?
Yes, but the result will be less accurate. An early ultrasound will give a more precise date.