Work out a due date from an IVF embryo transfer. Because IVF timing is known precisely, the estimate is counted straight from the transfer date, with a separate rule for day-3 and day-5 transfers.
Enter your transfer date to see the due date.
This tool gives an estimate only and is not medical advice. Your fertility clinic will confirm your due date, usually with an early scan.
An estimated due date is a guide. Most babies arrive in the weeks around it.
About this calculator
With IVF the timing of conception is known, which makes the due date easier to estimate than in a natural pregnancy. The calculator counts forward from the embryo transfer date. The number of days it adds depends on the embryo's age at transfer. A day-5 transfer uses a blastocyst, an embryo that has already developed for five days, so the due date is 261 days after the transfer. A day-3 transfer uses a younger embryo, so two more days are added, giving 263 days after the transfer.
An estimated due date marks the middle of a normal range rather than a fixed day, and a healthy birth commonly happens in the weeks on either side of it. A fertility clinic will usually confirm the date with an early ultrasound, which can adjust the estimate. This page covers the IVF method on its own because people going through IVF search for it specifically; the general pregnancy due date calculator also offers last-period, conception and ultrasound methods. The American Society for Reproductive Medicine and the American College of Obstetricians and Gynecologists publish patient guidance on IVF and pregnancy dating.
Frequently asked questions
How is an IVF due date calculated?
An IVF due date is counted from the embryo transfer date, because that is when the pregnancy timeline is fixed. A day-5 transfer uses a blastocyst that has grown for five days, and the due date is 261 days after the transfer. A day-3 transfer uses an embryo two days younger, so the due date is 263 days after the transfer. Both work back to the same full-term length of 40 weeks. The known timing is why IVF due dates are often more precise than dates estimated from a last period.
What is the difference between a day-3 and a day-5 transfer?
The number refers to how many days the embryo has developed in the laboratory before being transferred. A day-3 embryo has divided into roughly eight cells. A day-5 embryo has reached the blastocyst stage, with many more cells and a more developed structure. Clinics choose between them based on embryo quality and individual circumstances. For the due date, the two-day difference in embryo age is simply added in, so a day-3 transfer gives a due date two days later than a day-5 transfer on the same date.
Why does IVF have its own due date calculator?
The general method of dating a pregnancy counts 280 days from the last menstrual period, but that does not fit IVF, where there is no relevant last period and conception timing is known exactly. Using the wrong method would put the due date off by days. People who conceive through IVF also tend to search for IVF-specific guidance. So this calculator counts from the transfer date with the correct day-3 or day-5 rule, while the general pregnancy due date calculator covers the other methods.
How accurate is an IVF due date?
An IVF due date is usually a good estimate, helped by the precise timing of the transfer. Even so, it is an estimate. A due date is the middle of a normal range, and most babies arrive in the weeks around it rather than on the day. A fertility clinic confirms the date with an early ultrasound, which measures the embryo and can adjust the estimate. Treat the calculator result as a guide and follow your clinic's dating.
Does the IVF due date count from transfer or from conception?
It counts from the transfer date. With IVF, fertilisation happens in the laboratory, and the embryo is then grown for three or five days before being transferred. The calculator builds that laboratory time into the rule it uses, 261 days for a day-5 transfer and 263 days for a day-3 transfer. You do not need to work out a separate conception date. Just enter the transfer date and choose the transfer type.