IVF Due Date Calculator

Embryo transfer date

Embryo age at transfer

Estimated due date

weeks pregnant today

trimester

This estimate adds 266 days to your equivalent conception date, calculated from your transfer date and embryo age — the standard method fertility clinics use for IVF and FET due dates. Your clinic's own estimate, based on your specific protocol, should always take priority.

How this is calculated

Unlike a natural pregnancy, IVF gives us a known, exact "conception-equivalent" date — the transfer date minus the embryo's age. From there, the same 266-day rule applies:

Day 3 transfer: due date = transfer date + 263 days
Day 5 transfer: due date = transfer date + 261 days
Day 6 transfer: due date = transfer date + 260 days

Want to work backward from a due date instead? Try the Reverse Due Date Calculator.

Why IVF dating tends to be more precise

With a natural pregnancy, conception date is always an estimate built from an assumed ovulation day. With IVF or a frozen embryo transfer (FET), the embryo's age at transfer is a known, controlled number, so the "conception-equivalent" date isn't a guess — it's simply the transfer date minus the embryo's age. That's why IVF due dates are generally considered a bit more reliable than last-period-based estimates, and why your clinic's own dating usually takes priority over any general calculator.

Fresh transfers and frozen transfers use the same math once you know the embryo's age, so this calculator works for both. Day 6 transfers are less common than Day 3 or Day 5 but follow the identical logic — just two fewer days added than a Day 3 transfer, and one fewer than Day 5.

Things to know

This calculator assumes a single, straightforward transfer. If you're carrying twins from a double embryo transfer, keep in mind that twin pregnancies commonly arrive earlier than this due date — often several weeks before a singleton pregnancy would, so treat the estimate as a later-than-typical marker rather than the expected delivery day.

Every clinic tracks dates slightly differently, and some report an "embryo transfer day" that's already adjusted for age. If your clinic gave you a due date that differs from this one, trust your clinic — they know your specific protocol, hormone levels, and any adjustments made along the way.

In the days after transfer, most clinics monitor a beta hCG blood test, often repeated 48–72 hours apart to check that levels are roughly doubling as expected, before an early ultrasound confirms the pregnancy and its location a few weeks later. Those early milestones are a separate process from the due date shown here, but they're usually what your clinic uses to confirm dating before officially handing you off to ongoing prenatal care.

Sources

The 266-day-from-conception convention used here is standard obstetric practice for IVF and FET dating. For more on IVF, embryo transfer, and fertility treatment generally, see the American College of Obstetricians and Gynecologists (ACOG) and NICHD.