Due Date Calculator
Find out your estimated due date, how far along you are today, and when common prenatal checkups usually happen.
How it works
Every method is converted to the same starting point: the first day of your last period, which counts as week 0. Your due date is 40 weeks after that date, and your current week of pregnancy is simply the number of days since then, split into weeks and days.
Typical prenatal milestones
Timing varies by country and provider, but a dating ultrasound often happens between 8 and 13 weeks, first-trimester screening (including the nuchal translucency scan) around 11-13 weeks, second-trimester blood screening around 15-20 weeks, the anatomy scan around 18-22 weeks, and the glucose screening test for gestational diabetes around 24-28 weeks. From 37 weeks a baby is considered early term.
Not pregnant yet? Try the ovulation calculator. To count down to any date, use the days until calculator.
Estimates based on averages, not medical advice. Follow your doctor or midwife for test timing and care.
Frequently asked questions
How is the due date calculated?
The standard method (Naegele's rule) adds 280 days, or 40 weeks, to the first day of your last menstrual period. If your cycle is longer or shorter than 28 days, the date shifts by the difference. If you know the conception date, the due date is conception + 266 days. For IVF, it is a 3-day embryo transfer + 263 days or a 5-day transfer + 261 days.
Why does pregnancy start counting before conception?
Pregnancy weeks are counted from the first day of your last period (0 weeks 0 days), not from the day you conceived, because that date is easier to know. That is why many people are already 4 or 5 weeks pregnant by the time they get a positive test. "12 weeks 3 days" means 12 full weeks plus 3 extra days.
My doctor gave me a different due date. Which one is right?
Go with your doctor's date. An early ultrasound (usually between 8 and 13 weeks) measures the baby and often adjusts the due date. Only about 5% of babies arrive on their due date, and birth anywhere from 37 to 42 weeks is considered within the normal range.