IVF Due Date Calculator · Estimated Due Date from Embryo Transfer

IVF Due Date Calculator

Estimate your due date from embryo transfer or oocyte retrieval using ACOG dating rules, the clinical standard for IVF pregnancies

Your IVF details

What would you like to calculate from?

Embryo transfer date

Current date (for GA)

A Day 3 cleavage-stage embryo is transferred 3 days after fertilisation.

ACOG dating rule (Committee Opinion 700): For IVF pregnancies, the due date is assigned using the age of the embryo and the date of transfer. IVF dating is the most precise method available — more accurate than ultrasound or LMP.

Quick examples

Your IVF Due Date

Estimated due date

—

— gestational age — conception —

Gestational age today

—

Days remaining

— days

Trimester

—

Equiv. LMP

—

Pregnancy progress

1st trimester 2nd trimester 3rd trimester

Your IVF dating summary

Milestone	Date	Gestational age	Notes

Your IVF pregnancy timeline

Milestone	Gestational age	Date	Notes

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Creator & Maintainer

Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.

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IVF dating isn’t an estimate the way LMP dating is. The embryologist knows exactly how old the embryo was when it went in. A day-5 blastocyst transfer means the embryo was 5 days past fertilization at the moment of transfer. That single fact lets you calculate the due date with more precision than any other method in obstetrics.

The formula is straightforward once you know the embryo’s age: due date = transfer date + (266 − embryo age). A day-3 transfer adds 263 days. A day-5 blastocyst adds 261. A day-6 blastocyst adds 260. Oocyte retrieval, which is roughly equivalent to fertilization day, adds the full 266.

This calculator handles all four inputs. It also produces an “equivalent LMP” date, which is the LMP you’d report if you were dating the pregnancy the standard way. That’s useful when a clinic or lab asks for your LMP and you’d otherwise have to explain that you conceived via IVF. Numbers you enter stay in your browser.

How to Use the IVF Due Date Calculator

Pick the method: Day 3 transfer, Day 5 transfer, Day 6 transfer, or oocyte retrieval.
Enter the transfer date or retrieval date, depending on the method.
Set the current date so the tool can compute your gestational age today.
Read the hero panel. Your estimated due date appears in large type.
Scan the context row for gestational age today, conception date, and trimester.
Check the four tiles for gestational age, days remaining, trimester, and equivalent LMP.
Follow the progress bar to see where you sit across the three trimesters.
Scroll the two tables for a dating summary and a full pregnancy milestone timeline.

How the IVF Due Date Calculator Formula Works

Formula: Due date = transfer date + (266 − embryo age in days)

That’s the ACOG-endorsed approach. The 266-day figure is the standard interval from conception to delivery, and the embryo age at transfer tells you how far past conception the embryo already was.

Each transfer type maps to a specific offset:

Day 3 cleavage stage: due date = transfer + 263 days
Day 5 blastocyst: due date = transfer + 261 days
Day 6 blastocyst: due date = transfer + 260 days
Oocyte retrieval: due date = retrieval + 266 days

Gestational age at the moment of transfer follows the same logic, since gestational age is counted from the LMP, which sits 14 days before conception:

Day 3 transfer: 2 weeks 3 days (17 days)
Day 5 transfer: 2 weeks 5 days (19 days)
Day 6 transfer: 2 weeks 6 days (20 days)
Retrieval: 2 weeks 0 days (14 days)

Once the due date is set, the equivalent LMP is due date minus 280 days. Gestational age today is the number of days between the equivalent LMP and today. Days remaining is the gap from today to the due date. The tool flags gestational ages above 42 weeks or below zero as likely input errors, and the trimester labels follow the standard ACOG cutoffs: first through 13 weeks 6 days, second through 27 weeks 6 days, third from 28 weeks onward.

Worked Example

Suppose you transferred a day-5 blastocyst on March 4, 2026, and today is April 15, 2026.

Method: Day 5 blastocyst transfer
Due date = March 4 + 261 days = November 20, 2026
Conception date = March 4 − 5 days = February 27, 2026
Equivalent LMP = February 27 − 14 days = February 13, 2026
Gestational age today = 61 days = 8 weeks 5 days
Days remaining = 219
Trimester: First

The calculator would show November 20, 2026 in the hero panel, 8 weeks 5 days in the gestational age tile, and February 13, 2026 as the equivalent LMP. The dating summary table would list the transfer itself at 2 weeks 5 days, the estimated fertilization on February 27, and the due date at 40 weeks. The milestone table would highlight any dates that fall on today.

If the transfer had been a day-3 embryo instead, the due date would shift two days earlier to November 18. A day-6 blastocyst would push it one day later to November 21. Retrieval would land the due date on November 24. Same pregnancy, three different anchors, four slightly different due dates.

Frequently Asked Questions

How do you calculate a due date from IVF?

Due date = transfer date + (266 − embryo age). A day-3 transfer adds 263 days, a day-5 blastocyst adds 261, and a day-6 blastocyst adds 260. Oocyte retrieval adds the full 266 days.

Is IVF dating more accurate than ultrasound?

Yes. IVF dating uses the embryologist’s record of the embryo’s exact age at transfer. It’s the most precise method available and ACOG recommends using it when the pregnancy results from ART, even if an ultrasound suggests a slightly different date.

What is the due date for a day 5 transfer?

Due date = transfer date + 261 days. A day-5 blastocyst is already 5 days past fertilization at transfer, so the remaining interval to delivery is 261 days rather than the full 266.

Can I use the retrieval date instead of the transfer date?

Yes. Oocyte retrieval adds 266 days, since fertilization typically occurs on the day of retrieval. That gives you the same due date as a transfer calculation when you account for the embryo’s age at transfer.

Does frozen embryo transfer change the due date?

No. Frozen and fresh transfers use the same dating rule. The embryo’s developmental age at transfer is what matters, not how long it was stored.

What is the equivalent LMP for IVF?

The equivalent LMP is 14 days before the estimated fertilization date. It’s the date you’d report if you conceived naturally, and it keeps your dates consistent in systems that ask for an LMP.

How is gestational age calculated for IVF?

Gestational age is counted from the equivalent LMP. At a day-5 transfer, you’re already 2 weeks 5 days pregnant. The calculator shows gestational age today based on that anchor.

When is the first ultrasound after IVF?

Most clinics schedule it around 6 to 7 weeks of gestational age, which is 4 to 5 weeks after a day-5 transfer. The scan confirms intrauterine placement and checks for a heartbeat.

Can an ultrasound change my IVF due date?

Rarely. ACOG recommends using the IVF-derived date as the reference even if an early scan differs slightly. Redating is uncommon because the IVF date is the more precise anchor.

Does IVF dating apply to IUI pregnancies?

No. IUI doesn’t involve an embryo with a known developmental age, so there’s no ART-derived date to use. IUI pregnancies are dated from LMP or an early ultrasound.

What if I transferred two embryos?

The dating calculation is the same. Each embryo’s age is known, and the due date comes from the transfer date and embryo stage, not from the number transferred.

How many weeks is an IVF pregnancy?

An IVF pregnancy is 40 weeks from the equivalent LMP, or about 38 weeks from fertilization. The due date calculation reflects that same interval as any other pregnancy.

Disclaimer

This IVF due date calculator is for educational purposes only and is not medical advice. It applies the ACOG Committee Opinion 700 dating rule to the inputs you provide. Actual clinical dating involves your provider’s judgment, ultrasound findings, and sometimes adjustments based on how the pregnancy progresses. Always rely on your healthcare provider’s dating for decisions about screening windows, delivery timing, or any other clinical matter. If your calculator result and your clinic’s date disagree, your clinic’s date wins.