IVF Due Date Calculator
Enter the clinic-confirmed Day-3 or Day-5 transfer date to estimate an IVF due date.
The IVF dating guide explains the 261-day and 263-day counts.
Transfer-day arithmetic
This page dates a pregnancy from a completed embryo transfer. The inputs are the actual transfer date and a clinic-confirmed Day-3 or Day-5 embryo age. A last menstrual period is the wrong starting point here; that forward count lives on the Due Date Calculator. Weeks after the due date is known are the Gestational Age Calculator.
ACOG Committee Opinion 700 says that when a pregnancy results from assisted reproduction, the assisted-reproduction gestational age should be used to assign the estimated due date, using the age of the embryo and the date of transfer. Its examples match this calculator: a day-5 embryo is 261 days from the embryo replacement date, and a day-3 embryo is 263 days from that date.
The arithmetic is the 280-day pregnancy calendar minus the gestational age already reached on transfer day. A day-5 embryo is treated as 2 weeks and 5 days (19 days) of gestational age, and 280 − 19 = 261. A day-3 embryo is 2 weeks and 3 days (17 days), and 280 − 17 = 263. Equivalently, fertilization is placed at transfer date minus the embryo’s age in days, and the due date is that fertilization date plus 266 days. Both routes produce the same due date. The IVF dating guide explains the same counts in prose, and the methodology records the constants.
Fresh and frozen transfers both use the date the embryo was transferred in this cycle. ASRM’s international glossary treats gestational age for frozen-thawed embryos from the cumulative developmental age: culture time before freezing plus culture time after thawing or warming. Do not rebuild that age from the retrieval date, the freeze date, or the warming date. If the clinic has not confirmed Day 3 or Day 5, this form has no honest button to press.
Worked example
Transfer date: March 1, 2024. Day-5 embryo: March 1 + 261 days = November 17, 2024. On the day of transfer the pregnancy calendar already reads 2 weeks 5 days. Day-3 embryo, same transfer date: March 1 + 263 days = November 19, 2024, and the pregnancy age on transfer day is 2 weeks 3 days.
The two-day gap is the two-day difference in embryo age, not a statement about which transfer is more likely to succeed. A frozen embryo transferred on March 1 uses March 1 as well. The retrieval might have been in a different month or a different year; that earlier date stays out of the sum once the clinic has stated the developmental age at transfer.
To see the week count on a later calendar day, take the due date from this result, or the due date the clinic documented, and open the gestational age calculator. The pregnancy dating guide describes how those weeks are spoken after any due date is set.
How to read the IVF due date
The date is an estimated due date on the same 40-week pregnancy calendar used for other pregnancies. Committee Opinion 700’s examples fix the count from transfer. They do not turn the due date into a predicted birthday. Birth can fall before or after that day, just as it can after a period-based estimate.
Read the embryo age and the transfer date beside the result before comparing it with another site. A calculator that starts from egg retrieval, from a stimulated “period,” or from a pregnancy-test date is answering a different question. Intracytoplasmic sperm injection changes how fertilization is achieved in the laboratory; it does not change the 261-day or 263-day offset. Donor egg, donor embryo, or a gestational carrier likewise leaves those day counts in place when the embryo age and transfer date are known.
If the clinic has already written a due date in the record, that documented date is the one to use for prenatal care. Use this page to understand the arithmetic or to check a transfer record against it, not to average several dates until one looks preferable.
Limits and the clinic record
This calculator supports documented Day-3 and Day-5 transfers only. Day 2, Day 4, Day 6, Day 7, an unstated age, or two conflicting ages are reasons to use the clinic’s due date or to ask which developmental age was used. Choosing the nearest button would invent an embryo age.
The result does not estimate the chance of implantation, pregnancy, twins, or live birth, and it does not say whether a fresh or frozen transfer was the better plan. Ultrasound still matters clinically. Committee Opinion 700’s redating thresholds are for comparing ultrasound with a last-period date; an assisted-reproduction due date is assigned from embryo age and transfer date. This site cannot decide that a scan should replace the clinic date.
Questions about bleeding, pain, medication, or how you feel go to the fertility or prenatal clinician, or to local urgent care. This page does not interpret a pregnancy test, a hormone level, or symptoms.
Frequently asked questions
- Why does a Day-5 transfer use 261 days?
ACOG’s example treats the day-5 embryo as already 2 weeks and 5 days of gestational age on transfer day. The remaining time to a 280-day due date is 261 days. A day-3 embryo has two fewer days of development, so 263 days remain.
- Do frozen transfers use a different formula?
They use the same 261-day or 263-day offset from the actual transfer date, once the clinic confirms that the embryo’s total developmental age is Day 5 or Day 3. The freeze date does not replace the transfer date.
- What if my booklet lists a retrieval date and a transfer date?
Enter the transfer date, and enter Day 3 or Day 5 only if the clinic documented that age. Retrieval is an earlier laboratory step. Adding culture days yourself double-counts development the clinic has already included in the embryo age.
- Which due date should prenatal care follow?
The current due date in the fertility or prenatal record. Committee Opinion 700 says to determine the due date, discuss it, and document it, and to reserve later changes for uncommon situations that are also documented. An online recount is a check on the arithmetic, not a new clinical date.
Sources
These sources describe assisted-reproduction dating. They do not review or endorse Pregnancy Metrics.
- ACOG Committee Opinion 700 — Methods for Estimating the Due Date. Day-5 transfer plus 261 days, day-3 transfer plus 263 days, and assigning the due date from embryo age and transfer date.
- ASRM — International Glossary on Infertility and Fertility Care, 2025. Gestational age and cumulative embryo developmental age for frozen-thawed transfers.
- ACOG — When Pregnancy Goes Past Your Due Date. The due date remains an estimate on the 40-week calendar after it has been assigned.