Health & Fitness
Pregnancy Due Date Calculator
Estimate your baby's due date and current gestational age.
Pregnancy Due Date Calculator
Estimates only — always confirm with your healthcare provider.
How the due date is estimated
The standard method adds 280 days (40 weeks) to the first day of your last menstrual period. If your cycle is longer or shorter than 28 days, the estimate shifts accordingly.
Only about 4% of babies are born exactly on their due date. A due date is a window, not a deadline.
Frequently asked questions
How is the due date calculated?
It uses Naegele's rule: add 280 days to the first day of your last menstrual period, adjusted for your cycle length.
How accurate is it?
It's an estimate. An early ultrasound is more accurate. Only a small percentage of babies arrive exactly on the due date.
What is gestational age?
Gestational age is how far along the pregnancy is, counted in weeks and days from the first day of your last period.
Does a longer cycle change the date?
Yes. A longer cycle usually means ovulation happens later, so the due date moves later — the calculator adjusts for this.