When is your
baby due?
Calculate your due date using 5 different methods — Last Period, Due Date, Conception Date, Ultrasound, or IVF Transfer Date. Get your trimester, weeks pregnant, baby size, and milestone tracker instantly.
Last Period (LMP)
Most common method — enter the first day of your last period
Due Date
Already have a due date? Work backwards to see weeks pregnant
Conception Date
Know when you conceived? Get an accurate due date instantly
Ultrasound
Use your scan date and gestational age from the sonographer
IVF Transfer
Supports Day 3, Day 5, and Day 6 embryo transfers
When is your baby due?
Choose your calculation method below
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Frequently asked questions
How is the due date calculated from last period?
The due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is the standard Naegele's rule used by most doctors.
How does the ultrasound due date calculation work?
Enter the date of your ultrasound scan and how many weeks pregnant you were at that scan. The calculator works backwards to estimate your LMP and then adds 280 days to find your due date.
How is IVF due date calculated?
For IVF, the due date is calculated from the embryo transfer date. A Day 5 blastocyst transfer adds 261 days (280 minus 19 days). A Day 3 transfer adds 263 days.
What are the three trimesters of pregnancy?
The first trimester covers weeks 1–13, the second trimester covers weeks 14–27, and the third trimester covers weeks 28–40. Each trimester has key developmental milestones.