How is IVF due date calculated from a day-5 transfer?

Educational ART dating on this site uses transfer date + 261 days for a day-5 blastocyst, reflecting gestational age of about 2 weeks + 5 days at transfer relative to a 280-day EDD framework.

What about day-3 embryo transfers?

Day-3 transfers use transfer date + 263 days (gestational age about 2 weeks + 3 days at transfer).

Can I use fertilization or egg-retrieval date instead?

Yes. That optional mode treats the date as conception-equivalent and adds 266 days. Prefer transfer date and embryo age when both are known.

Should I still use an LMP calculator for IVF?

ART pregnancies should prioritize embryo age and transfer date rather than ordinary LMP rules.

Pregnancy Metrics

IVF Due Date Calculator

Free IVF due date calculator using ART-derived dating from day-3 or day-5 embryo transfer, with an optional fertilization/egg-retrieval mode. Not mixed with ordinary LMP rules.

Pregnancy calculators and fetal growth reference tools for educational use.

Plain-language interpretation

In IVF/ART, embryo age at transfer is known more precisely than LMP ovulation assumptions. This tool converts transfer date (and embryo day) into an educational estimated due date and shows gestational age on the transfer day and on your assessment date.

Formula and dating standard

Day-5 blastocyst transfer: transfer date + 261 days
Day-3 embryo transfer: transfer date + 263 days
Fertilization / egg retrieval: date + 266 days
Gestational age at day-N transfer ≈ 14 + N days (LMP-equivalent frame)

Important assumptions

Uses ART-derived dating only—does not blend with LMP rules.
Unlike LMP calculators that assume roughly 28-day cycles and day-14 ovulation, this page relies on embryo age and transfer (or fertilization) timing.
Clinic protocols may document EDD slightly differently.
Ultrasound and clinical records still guide formal obstetric dating.

Applicable use

Educational dating after IVF/ICSI or related ART when transfer date and embryo age (or fertilization date) are known.

Worked example

Day-5 transfer on 2024-03-01 → EDD 2024-11-17 (261 days later). Gestational age on transfer is 2 weeks, 5 days. Day-3 transfer on the same date → EDD 2024-11-19 (263 days).

Limitations

Not a clinic treatment plan or success predictor.
Does not model frozen embryo thaw nuances beyond embryo day input.
Does not replace your fertility or obstetric care team.

References

ACOG Committee Opinion — Methods for Estimating the Due Date (includes ART dating principles)
Educational ART day-count offsets: day-5 +261, day-3 +263, fertilization +266 relative to a 280-day EDD framework.

Frequently asked questions

How is IVF due date calculated from a day-5 transfer?: Educational ART dating on this site uses transfer date + 261 days for a day-5 blastocyst, reflecting gestational age of about 2 weeks + 5 days at transfer relative to a 280-day EDD framework.
What about day-3 embryo transfers?: Day-3 transfers use transfer date + 263 days (gestational age about 2 weeks + 3 days at transfer).
Can I use fertilization or egg-retrieval date instead?: Yes. That optional mode treats the date as conception-equivalent and adds 266 days. Prefer transfer date and embryo age when both are known.
Should I still use an LMP calculator for IVF?: ART pregnancies should prioritize embryo age and transfer date rather than ordinary LMP rules.

Last content review: 2026-07-18. Formula version: pregnancy-dates-v1.