IVF Due Date Calculator 🔬
The most precise due date calculation for IVF pregnancies. Enter your embryo transfer date for Day 3 or Day 5 transfers.
How the IVF Due Date Calculator Works
The IVF due date calculator provides the most precise estimated due date of any pregnancy dating method. This is because, unlike natural conception, the exact age of the embryo is known at the time of transfer. There is no guesswork about ovulation timing or when fertilization occurred — the embryology lab has documented every step.
The calculation is based on the principle that a full-term pregnancy lasts 266 days (38 weeks) from the date of conception. In IVF, the date of conception is the day of egg retrieval and fertilization, which is known precisely. For a Day 3 embryo transfer, the embryo is 3 days old at transfer, so we add 263 days (266 minus 3) to the transfer date. For a Day 5 blastocyst transfer, the embryo is 5 days old, so we add 261 days (266 minus 5).
Day 3 embryos, also known as cleavage-stage embryos, typically consist of 6 to 10 cells. They are transferred earlier in development when there is less information about which embryos are most likely to implant. Day 5 embryos, called blastocysts, have developed further into approximately 100+ cells and have formed two distinct cell types: the inner cell mass (which becomes the baby) and the trophoblast (which becomes the placenta). Blastocyst transfers generally have higher implantation rates because the embryo has demonstrated its ability to develop past the critical cleavage stage.
This calculator works identically for both fresh and frozen embryo transfers (FET). What matters is the day of development at the time of transfer. A Day 5 blastocyst that was frozen and later thawed is still a Day 5 embryo when transferred, so the same 261-day formula applies.
Most reproductive endocrinologists consider the IVF transfer date calculation to be the gold standard for pregnancy dating. While an early ultrasound may still be performed to confirm viability and growth, the transfer-based due date is rarely changed unless ultrasound measurements differ significantly. This precision is one of the unique advantages of IVF pregnancies from a dating perspective.