Calculator
Pregnancy Due Date Calculator
Estimate your baby's due date using one of three standard methods. Enter a single date and we'll calculate the rest — no signup or tracking required.
Enter a date above to see your estimated due date.
How this calculator works
This tool uses three accepted obstetric dating methods. The default and most common is Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last menstrual period (LMP). If you know the conception date, we add 266 days (38 weeks) instead. For IVF pregnancies, dating depends on the embryo age at transfer — a day-5 blastocyst transfer adds 261 days, and a day-3 transfer adds 263 days.
Whichever method you pick, the calculator also estimates your conception date and your current gestational age in weeks + days, along with the matching trimester (1st: weeks 0–12, 2nd: weeks 13–26, 3rd: weeks 27–40).