IVF Due Date Calculator — Embryo Transfer
After IVF or a frozen embryo transfer (FET), your due date can be calculated very precisely because the exact age of the embryo and the transfer date are both known. Select whether you had a Day-3 (cleavage-stage) or Day-5 (blastocyst) transfer and enter the transfer date. A Day-5 blastocyst is dated as 19 days of gestation on the transfer day; a Day-3 embryo as 17 days. Enter your details for the EDD and full pregnancy timeline.
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Frequently asked questions
How is the due date calculated for an IVF or FET pregnancy?+
For a Day-5 blastocyst transfer, the due date is 261 days after the transfer date; for a Day-3 cleavage-stage transfer it is 263 days. This works because the embryo's exact age is known, so the date of fertilisation — and therefore the due date — is far more certain than with natural conception.
Is an IVF due date more accurate than an LMP due date?+
Yes. Because the day of fertilisation is known precisely in IVF, the due date is more accurate than one estimated from the last menstrual period, especially for women with irregular cycles. Your clinic will still confirm dating with an early ultrasound.
Does it matter if my transfer was a fresh or frozen (FET) cycle?+
No — the calculation depends only on the embryo's age at transfer (Day-3 or Day-5), not on whether it was a fresh or frozen transfer. Select the embryo day and enter your transfer date.
How is the pregnancy due date calculated?+
The standard estimated due date (EDD) is 40 weeks (280 days) from the first day of your last menstrual period (LMP) using Naegele's rule. If you know your conception date, IVF transfer date, or a scan-dated gestational age instead, this calculator works backwards from those to the same EDD. Only about 5% of babies are born on their exact due date — most arrive within two weeks either side.
What is EDD in pregnancy?+
EDD stands for Estimated Due Date — the date your baby is expected to arrive, calculated as 40 weeks from your last menstrual period. It is an estimate, not a deadline: a normal, full-term birth can happen any time from 37 to 42 weeks.
Which dating method is the most accurate?+
A first-trimester ultrasound (crown-rump length, ideally before 14 weeks) is the most accurate way to date a pregnancy and is what doctors use to confirm or revise the due date. LMP dating is reliable only if your cycles are regular and you remember the date. For IVF, the transfer date gives a very precise due date because the day of fertilisation is known.
When does each trimester start and end?+
First trimester: weeks 1–12. Second trimester: weeks 13–26. Third trimester: weeks 27–40. This calculator shows your current trimester, your week-by-week progress, and key appointment milestones such as the NT scan (11–13 weeks) and anomaly scan (around 20 weeks).
How many weeks pregnant am I right now?+
Gestational age is counted from the first day of your last period, not from conception — so you are already counted as about 2 weeks pregnant at the moment of conception. Enter your date above and the calculator shows your current weeks and days, your trimester, and how many weeks remain.