Pregnancy Due Date Calculator
Estimate your due date and pregnancy weeks based on your last menstrual period.
A helpful tool to estimate how many weeks pregnant you are and when your baby may arrive.
Due date calculator
w.1–13
w.14–27
w.28–40
Your due date is an estimate. Most babies arrive between weeks 38 and 42. Always confirm with your midwife or doctor.
What is an estimated due date?
A due date is an estimation of when your baby may be born.
Most pregnancies last around 40 weeks from the first day of the last menstrual period.
How is the due date calculated?
Most calculators use Naegele’s rule, which adds 40 weeks to the first day of the last menstrual period.
First trimester ultrasounds can also help adjust the estimated due date, especially if menstrual cycles are irregular.
How many weeks pregnant am I?
Pregnancy weeks are counted from the first day of the last menstrual period, not from the day of conception.
This means that during the first two weeks of pregnancy there is technically no pregnancy yet, but they are still part of the standard medical calculation.
FAQ
Is it normal to give birth before or after the due date?
Yes. Most babies are not born exactly on their estimated due date.
Can the due date change?
Yes, especially during the first trimester if the ultrasound measurements suggest a different gestational age.
When is a pregnancy considered full term?
Between 37 and 42 weeks of pregnancy.
If I have irregular cycles, is the calculator reliable?
It provides an estimate, but early ultrasounds are usually more accurate.
If you’re pregnant and would like to feel more informed, calm, and supported during pregnancy, birth, or postpartum, you can explore my doula services here or send me a message and we can talk.