Enter your embryo transfer date and embryo age (day 3, 5, or 6) to estimate your IVF or frozen embryo transfer (FET) due date, current week, and equivalent LMP.
IVF dating usually starts from embryo transfer date and embryo age, which can be more relevant than relying only on last menstrual period.
This estimate is for planning and education only. Your clinic or prenatal care provider should confirm official dating.
This calculator works for both fresh and frozen embryo transfers (FET). What matters for dating is the embryo's age on the day of transfer, not whether it was frozen — so a day-5 blastocyst is dated the same way whether it is fresh or thawed.
For a 5-day transfer (blastocyst), the due date is the transfer date plus 261 days; for a 3-day embryo it is plus 263 days; for a day-6 blastocyst, plus 260 days. The calculator adjusts automatically when you choose the embryo age.
The estimated due date for twins is worked out the same way from your transfer date — carrying multiples does not change the dating method. However, twins are often born earlier than a single baby and are monitored more closely, so your clinic may plan an earlier delivery date.
To follow your pregnancy week by week, use the pregnancy week calculator; to understand why dates can shift, read why your due date can change.