IVF Due Date Calculator

Q: What formula does this IVF due date calculator use?

The calculator adds 266 minus your embryo day to your transfer date. For a Day 5 blastocyst, it adds 261 days. For a Day 3 embryo, it adds 263 days. This is the same method most fertility clinics use.

Updated Jun 6, 2026 By Jehan Wadia

Introduction

If you had an IVF (in vitro fertilization) embryo transfer, this calculator helps you find your estimated due date. It works for fresh transfers, frozen embryo transfers (FET), and any transfer day from Day 0 (egg retrieval) through Day 5 (blastocyst) or beyond. Just enter your transfer date and embryo day, and the tool does the math for you.

The calculator uses a simple formula: it adds 266 days minus your embryo's age to your transfer date. For example, a Day 5 blastocyst transfer adds 261 days. This method is the same one fertility clinics use to estimate when your baby will arrive.

Along with your due date, you will also see your current gestational age, estimated conception date, time remaining until delivery, a pregnancy milestone timeline, a progress chart, and a full week-by-week breakdown with baby size comparisons. These details help you track your pregnancy from start to finish. You can also use our Pregnancy Weight Gain Calculator to monitor healthy weight changes throughout each trimester.

Keep in mind that this tool gives an estimate only. Your doctor may adjust your due date based on ultrasound measurements or other factors. Always follow the guidance of your healthcare provider for the most accurate information about your pregnancy.

How to Use Our IVF Due Date Calculator

Enter a few details about your embryo transfer, and this calculator will give you an estimated due date, your current gestational age, a milestone timeline, and a full week-by-week pregnancy breakdown.

Embryo Transfer Day: Pick the day of your embryo when it was transferred. Choose Day 0 if you are using your egg retrieval date, Day 3 for a cleavage-stage embryo, or Day 5 for a blastocyst. You can also type any number from 0 to 10 in the box.

Transfer or Retrieval Date: Enter the date your embryo transfer or egg retrieval took place. This must be today or a date in the past. If you need help calculating exact durations between dates, our Date Duration Calculator can assist.

Transfer Type: Select Fresh Transfer or Frozen Transfer (FET). This label is for your reference only and does not change the due date result.

Calculate Button: Press "Calculate" to see your results. Press "Reset" to clear everything and start over.

An IVF due date calculator helps you figure out when your baby will likely be born after an in vitro fertilization (IVF) transfer. In IVF, eggs are taken from the ovaries, fertilized in a lab, and then placed back into the uterus. This is called an embryo transfer. The transfer can happen on different days after fertilization, most commonly on day 3 or day 5. A day 5 transfer is called a blastocyst transfer and is the most common type today. For a more general pregnancy timeline estimate, you may also want to check our Due Date Calculator, which works from your last menstrual period.

The way this calculator works is simple. It takes your transfer date and the embryo day number, then counts forward to find your estimated due date. The formula uses 266 days (the average length of a pregnancy from conception) minus the embryo day to figure out how many days to add from your transfer date. For example, if you had a day 5 blastocyst transfer, the calculator adds 261 days to your transfer date.

Fresh vs. Frozen Transfers

There are two main types of IVF transfers. A fresh transfer means the embryo is placed in your uterus during the same cycle the eggs were retrieved. A frozen embryo transfer (FET) means the embryo was frozen and transferred in a later cycle. Both types use the same due date formula. The only thing that matters for the calculation is the embryo day and the date of transfer.

How Gestational Age Works in IVF

Gestational age is counted from the start of your last menstrual period (LMP). In natural pregnancies, doctors use the first day of your last period to count. But with IVF, there may not be a natural LMP to use. Instead, the calculator figures out a theoretical LMP by counting backward 280 days from your due date. This lets your doctor track your pregnancy the same way they would for any other pregnancy. If you are trying to pinpoint when conception likely occurred, our Conception Calculator can help, and our Ovulation Calculator is useful for understanding fertility windows in natural cycles. You might also find the Age Calculator handy once your baby arrives to track milestones by exact age.

What to Know About Your Due Date

A due date is an estimate, not an exact date. Most babies are born within two weeks before or after the due date. Only about 5% of babies arrive on the exact estimated date. Your doctor may adjust your due date based on ultrasound measurements during your first trimester. Always follow the guidance of your healthcare provider over any online calculator. As your pregnancy progresses, tools like the BMI Calculator, Calorie Calculator, and Water Intake Calculator can help you stay on top of your overall health, while the Sleep Calculator can support good rest habits throughout each stage. Once your little one arrives, our Baby Percentile Calculator is a great way to track their growth.

Frequently asked questions

What formula does this IVF due date calculator use?

The calculator adds 266 minus your embryo day to your transfer date. For a Day 5 blastocyst, it adds 261 days. For a Day 3 embryo, it adds 263 days. This is the same method most fertility clinics use.

Can I use this calculator for a Day 0 egg retrieval date?

Yes. Select Day 0 in the quick-select buttons or type 0 in the day field. Then enter your egg retrieval date. The calculator will add 266 days to that date to find your estimated due date.

Does it matter if I had a fresh or frozen transfer?

No. The due date formula is the same for both. The fresh or frozen label is just for your own reference. Only the embryo day and the transfer date affect the result.

What is a blastocyst transfer?

A blastocyst transfer is when the embryo is placed in your uterus on Day 5 after fertilization. By Day 5, the embryo has grown to around 70 to 100 cells and is called a blastocyst. This is the most common type of IVF transfer today.

Why does the calculator show a gestational age higher than my actual pregnancy length?

Gestational age counts from a theoretical last menstrual period (LMP), which is about two weeks before conception. So gestational age is always roughly two weeks more than the actual age of your embryo. This is standard for all pregnancies, not just IVF.

What does the current gestational age result mean?

It tells you how far along you are in your pregnancy right now. It is measured in weeks and days from your calculated LMP date. Your doctor uses this number to track your baby's growth and schedule tests.

How accurate is this IVF due date estimate?

It gives a good estimate, but most babies are born within two weeks before or after the due date. Only about 5% of babies arrive on the exact date shown. Your doctor may adjust it based on ultrasound scans.

Can I enter a future transfer date?

No. The calculator only accepts today's date or a date in the past. If your transfer has not happened yet, come back on the day of your transfer or after to use this tool.

What embryo day numbers can I enter?

You can enter any whole number from 0 to 10. The most common values are Day 0 (retrieval), Day 3 (cleavage stage), and Day 5 (blastocyst). Day 6 transfers are also used sometimes when a blastocyst needs an extra day to develop.

What is the estimated conception date shown in the results?

It is the estimated date your egg was fertilized. The calculator finds it by subtracting the embryo day number from your transfer date. For a Day 5 transfer on January 10, the conception date would be January 5.

What do the trimesters in the week-by-week table mean?

The first trimester is weeks 1 through 13. The second trimester is weeks 14 through 27. The third trimester is weeks 28 through 40 and beyond. Each trimester marks a different stage of your baby's development.

Why does the table go up to week 42?

Most pregnancies last about 40 weeks, but some go longer. The table includes weeks 41 and 42 because some babies arrive a little late. Doctors usually monitor you closely if you go past 40 weeks.

What does the progress chart show?

The donut chart shows how much of your pregnancy is complete as a percentage. It compares your current gestational age against the full 280-day (40-week) pregnancy. It updates each time you press Calculate.

What does full term mean in the milestone timeline?

Full term begins at week 39. This means your baby is fully developed and ready to be born. Babies born between 39 and 40 weeks are considered full term by medical standards.

Can I use this calculator if I had a Day 6 blastocyst transfer?

Yes. Type 6 in the embryo day field. The calculator will add 260 days (266 minus 6) to your transfer date to estimate your due date.

Should I use this calculator instead of my doctor's due date?

No. This tool gives a helpful estimate, but your doctor's due date is more accurate. Doctors use ultrasound measurements and your medical history to set or adjust your due date. Always follow your healthcare provider's guidance.

IVF Due Date Calculator

Introduction

How to Use Our IVF Due Date Calculator