IVF due date calculator
Estimate your due date from a day-3 or day-5 embryo transfer.
Direct answer:add 261 days to a day-5 blastocyst transfer, or 263 days to a day-3 transfer, to estimate a 40-week due date. Your clinic's own dating is the number to record.
This adds 261days to your transfer date—261 days for a day-5 blastocyst, 263 days for a day-3 embryo—the offsets fertility clinics commonly use. Your clinic's dating from retrieval or transfer is the number to trust.
Add your transfer date to begin.
Why IVF dating works differently
A typical due date is estimated 280 days from the first day of the last menstrual period. IVF pregnancies skip that guesswork because the fertilization or transfer date is known precisely, so the calculation instead starts from the transfer date and adds the days needed to reach an equivalent 40 weeks.
Once you have an estimate, our week-by-week trimester guide can help you follow what typically happens next, and the due-date explainer covers how clinical dating methods compare.
Common questions
How is an IVF due date calculated?
Clinics commonly estimate a due date by adding 261 days to a day-5 (blastocyst) transfer date, or 263 days to a day-3 transfer date. Both approximate 40 weeks from an equivalent last-menstrual-period date.
Why is a day-3 offset different from day-5?
A day-5 embryo is two days more developed than a day-3 embryo, so fewer days are added to reach the same 40-week milestone. The gap between the two offsets is exactly two days.
Is IVF due-date dating more accurate than LMP dating?
Generally yes. Because the fertilization date is known precisely, IVF pregnancies typically have more accurate dating than estimates based on the last menstrual period alone.
Will my clinic use the same due date this calculator gives?
Usually, but always confirm with your fertility clinic or OB. They may adjust dating slightly based on your specific protocol, retrieval date or early ultrasound measurements.
More tools for your timeline
See the twin due date calculator if you're expecting more than one, or the pregnancy week calculator to track weeks as they pass.