Calculate your due date from your IVF egg retrieval or embryo transfer date (3-day or 5-day transfer).
Estimated Due Date
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This is an estimate based on standard IVF dating formulas, for general information only — it is not medical advice. Your fertility clinic's records and your first ultrasound are the most reliable way to confirm your due date.
A full-term pregnancy lasts about 266 days from fertilization. With IVF, the exact age of the embryo at transfer is known, so instead of estimating backward from a last menstrual period, the due date is calculated forward from a known date — egg retrieval or embryo transfer.
The Formula
Egg retrieval date: add 266 days. Day 3 embryo transfer: add 263 days (266 − 3). Day 5 blastocyst transfer: add 261 days (266 − 5).
Fewer days are added for later-stage transfers because the embryo has already spent that many days developing in the lab — those days still count toward the pregnancy.
Fresh vs. Frozen Transfers
The calculation is identical for fresh and frozen embryo transfers (FET). What matters is the embryo's developmental age at the time of transfer — a frozen Day 5 blastocyst is still biologically 5 days old when thawed and transferred, so the same +261 day formula applies.
A Note on Accuracy
IVF due dates are generally more precise than natural-conception estimates since the embryo's exact age is known. Even so, only a small share of babies are born on their exact due date — most arrive within about two weeks of it. Twin and multiple pregnancies often deliver earlier than a single due date suggests.
Frequently Asked Questions
A full-term pregnancy is about 266 days from fertilization. Add 263 days to a Day 3 transfer date, or 261 days to a Day 5 (blastocyst) transfer date. For an egg retrieval date, add the full 266 days.
Egg retrieval happens around fertilization, so the full 266-day pregnancy length applies. An embryo transferred on Day 3 or Day 5 has already completed that many days of lab development, so fewer days are added from the transfer date to reach the same due date.
No. The formula is identical for fresh and frozen transfers. What matters is the embryo's developmental age at transfer — time spent frozen doesn't count toward development.
IVF due dates are generally more precise than natural-conception estimates, since the embryo's exact age is known rather than estimated. Still, your clinic's ultrasound dating remains the most reliable confirmation.
The formula itself doesn't change, but multiples pregnancies commonly deliver earlier than a single due date suggests — often several weeks before. Your specialist will monitor a multiples pregnancy more closely.