Why are 3-day and 5-day dates different?

Embryo age at transfer affects gestational dating. Blastocysts (day 5) are further developed than day-3 embryos, so the offset days differ.

Should I trust this over my clinic?

Always follow your fertility clinic's official dating — they may adjust for lab protocol or ultrasound findings.

Calculate your estimated due date from embryo transfer day (3-day or 5-day).

Embryo Transfer Date

Embryo Day

Estimated Due Date

Friday, Apr 23, 2027

How to use this calculator

Frequently Asked Questions

How to Use

What it calculates

Calculates estimated due date (EDD) from embryo transfer date for 3-day or 5-day (blastocyst) embryos.

When to use it

Use after IVF transfer to estimate EDD when your clinic has not yet provided one.

Formula

EDD = transfer date + 261 days (5-day embryo) or + 263 days (3-day embryo), per clinical IVF dating conventions.

Example

5-day blastocyst transfer on March 1 → EDD around November 17.

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