Calculate an estimated due date calculated from an embryo transfer date and embryo day. The calculator runs entirely in your browser and pairs a focused answer with the method, assumptions and the related tools worth checking next.
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Review the inputs and select Calculate.
Enter the embryo transfer date and the embryo day (Day 3, 5 or 6). The calculator treats the embryo's age at transfer as pregnancy time already elapsed and counts forward to a 280-day term: due date = transfer date + 280 − 14 − embryo day, in days.
A Day 5 transfer leaves 261 days to the due date; a Day 3 transfer leaves 263 and a Day 6 transfer 260. The page also works back to the implied LMP (due date minus 280 days) so it can show gestational age today and the trimester.
A Day 5 transfer on 10 March 2026 gives an estimated due date of Thursday 26 November 2026, with an implied LMP of 19 February 2026. On 20 October 2026 that is 34 weeks, 5 days — 37 days before the due date.
The same 10 March 2026 transfer at Day 3 gives 28 November 2026, two days later, so check the embryo day before relying on the date. This is an estimate from the standard 280-day model; as the calculator itself notes, clinical and ultrasound dating take precedence.
Enter the transfer date and embryo day, then select Calculate. Each step below is a short action rather than a wall of explanation.
Use the most reliable source value available for this input.
Use the most reliable source value available for this input.
Read the result, then copy, print or share a link that reopens the same inputs.
Work backwards to the implied last menstrual period, then apply the standard 280-day model forward.
Similar tools answer different questions. Match the inputs and the reference point to the answer you actually need.
The numbers come from your inputs; this shows the shape of the calculation.
Enter the date of the embryo transfer — the due date is counted forward from it.
Choose Day 3, Day 5 or Day 6: the embryo's age counts as pregnancy time already elapsed, so a Day 5 transfer leaves 261 days to the due date and a Day 3 leaves 263.
Transfer date + 280 − 14 − embryo day: a Day 5 transfer on 10 March 2026 gives an estimated due date of Thursday 26 November 2026. An estimate from the standard 280-day model; clinical and ultrasound dating can differ.
Use exact source inputs, keep the reference date visible and verify any official rule separately.
Set the reference date to the event that actually controls the decision, not to today.
Compare the stated method here against the other tool's convention before assuming an error.
For a neighbouring calculation, open the Gestational Age Calculator or the Pregnancy Due Date Calculator. To understand the reasoning first, read Corrected Age for Premature Babies: A Parent-Friendly Guide.
Choose another focused tool when the underlying question changes.
Understand the calendar rules, edge cases and next steps behind this calculator.
Answers about method, inputs, privacy, boundaries and responsible interpretation.
The calculator treats the embryo's age at transfer as pregnancy time already elapsed and counts forward to a 280-day term: due date = transfer date + 280 - 14 - embryo day, in days. A Day 5 transfer therefore leaves 261 days to the due date, a Day 3 transfer leaves 263, and a Day 6 transfer leaves 260.
Gestational age is counted from the first day of the last period, roughly 14 days before conception. The embryo day counts the days since conception, so adding those 14 days puts the transfer on the same gestational-age clock that the 280-day model uses.
A Day 5 transfer on 10 March 2026 gives an estimated due date of Thursday 26 November 2026, with an implied LMP of 19 February 2026. On 20 October 2026 that is a gestational age of 34 weeks, 5 days, with 37 days left to the due date.
The due date moves with it. The same 10 March 2026 transfer at Day 3 gives 28 November 2026, two days later than the Day 5 result, so check the embryo day from your treatment record before relying on the date.
It is an estimate from the standard 280-day model, worked out from the transfer date and embryo day alone. Clinical dating and ultrasound measurements take precedence over any calculator.
Navjeet Kamboj is the author and editor of Age Calculator Lab. He focuses on making age, date, milestone and planning calculations easier to understand through clearly explained methods, practical examples and responsible limitations.