Is an IVF due date more accurate than LMP?

It is more specific when embryo age is known. It is still an estimate — about 4–5% of babies arrive on the exact calendar day.

Do I enter the freeze date for FET?

No. Enter the day the embryo was transferred into the uterus.

Can I use this for IUI?

Yes — choose donor/IUI and enter the insemination date. IUI dating is looser than a known blastocyst transfer.

A small step today, a brighter tomorrow

Calculate Your IVF Due Date

IVF and FET due dates start from a clinic date plus embryo age — not a guessed last period. Use the calculator, then read how Day 3, Day 5, and frozen transfer math actually differ.

Try the Calculator → Pregnancy Guide

266 days − embryo age Private in your browser Edited by Dr. Farhan

Different Journey
Same Beautiful
Destination Pregnant woman in a pink cardigan smiling at her baby bump by a sunny window

How the math works

Day 3, Day 5, and FET are not the same calendar

Human pregnancy is commonly counted as 266 days from fertilization. IVF already recorded how old the embryo was on transfer morning, so you subtract that age and add the rest to the clinic date. That is why this site does not start from a period-app LMP unless you explicitly choose LMP.

What you enter	Gestational age that morning	Add for due date
Egg retrieval / IUI / donor egg	2 weeks 0 days	266 days
Day 3 embryo transfer	2 weeks 3 days	263 days
Day 5 blastocyst (fresh or FET)	2 weeks 5 days	261 days
Day 6 blastocyst	2 weeks 6 days	260 days
Day 7 blastocyst	3 weeks 0 days	259 days

Worked example: a Day 5 blastocyst transferred on 12 May 2025 has an educational due date of 28 January 2026 (transfer + 261). On 27 June 2025 that pregnancy is 9 weeks 2 days. A Day 3 transfer on the same calendar morning would be due two days later, because the embryo was two days younger.

FET: enter the thaw-and-transfer day. Freeze date, first estrogen pill, and last cycle’s retrieval do not belong in the box. Time in the tank does not add pregnancy days. A frozen Day 5 blastocyst is still five days old when it is placed.

Limits: about 4–5% of babies arrive on the exact calendar day. A first-trimester scan within about five days often keeps the IVF date; later scans are worse at dating. This homepage is not a clinic chart. Confirm with the team that has your records. Edited by Dr. Farhan. Associated with Ghazi Hospital. Educational only — not medical advice; confirm care with your own clinic.

Open the IVF due date calculator · IVF pregnancy guide after transfer · Dating FAQs

Transfer-based mathDay 3 = +263 · Day 5 = +261

Private in the browserDates are not stored on our server

Named editorChecked against public ART dating rules

Guides after transferScans, betas, and when to call clinic

More Than a Date
It’s a Milestone

Use the calculator for the educational due date, then the pregnancy guide for what clinics typically schedule after transfer. Neither page replaces your nurse line.

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