Calculator
IVF Due Date Calculator
IVF pregnancies are dated from the embryo transfer date, not your last menstrual period. Pick your transfer-day type (day 3 or day 5) and enter the transfer date below.
Enter a date above to see your estimated due date.
Why IVF dating is different
In a natural cycle, obstetric dating counts from the first day of the last menstrual period (LMP) and assumes ovulation around day 14. With IVF you know the exact age of the embryo at transfer, so the conventional “LMP + 280” rule is replaced by embryo-specific adjustments:
- Day-5 blastocyst transfer: due date = transfer date + 261 days
- Day-3 cleavage transfer: due date = transfer date + 263 days
Both formulas produce the same due date as a natural conception that would have happened on the day the embryo reached its biological age — so an IVF day-5 transfer is dated as if ovulation occurred five days before the transfer.
Because of this, clinics often assign an “estimated LMP” for IVF pregnancies purely for paperwork and ultrasound comparison. This calculator shows that implied LMP alongside your due date so your care team can cross-check with growth scans.