# When is my IVF due date?

Works out the due date of an IVF pregnancy from the embryo transfer date and the embryo’s age (day 3, 5, or 6), as ACOG recommends, and how many weeks pregnant that is on a date.

- Page: https://www.acalculator.org/health/ivf-due-date-calculator
- JSON spec: https://www.acalculator.org/health/ivf-due-date-calculator.json
- Version: f3e58b34f963

## Default answer

Example with the default inputs (Embryo transfer date September 8, 2026, Embryo age at transfer Day 5, How far along on September 29, 2026) on the example date Tuesday, September 29, 2026: With a Day 5 embryo transferred on September 8, 2026, your due date is May 27, 2027.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| transfer | Embryo transfer date | The day the embryo was transferred to the uterus. |
| embryo | Embryo age at transfer | Days from egg retrieval and fertilization to the transfer: day 3, day 5 (blastocyst), or day 6. |
| on | How far along on | The date to count the weeks of pregnancy on. Today, unless you change it. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| due | Due date | The estimated due date: transfer date + 266 days − embryo age. |
| fertilization | Egg retrieval and fertilization | The transfer date less the embryo’s age in days. |
| dated | Pregnancy dated from | The equivalent first day of a last period: 280 days before the due date. |
| weeks | Weeks pregnant | Weeks and days of pregnancy on the chosen date, counted from the equivalent last period. |
| left | Days until the due date | Days from the chosen date to the due date. |

## Method

Due date = transfer date + 266 days − embryo age in days (261 days for a day-5 embryo, 263 for day 3); weeks pregnant are counted from the due date − 280 days.

## Assumptions

- Fertilization is on the egg retrieval day, so the embryo age counts days since fertilization.
- A pregnancy lasts 266 days from fertilization, which is 280 days from an equivalent last period two weeks earlier (ACOG).
- The same rule applies to fresh and frozen embryo transfers, because it uses the embryo’s age, not the calendar.
- Weeks pregnant show from the dated start of pregnancy to the due date. This is an estimate for information, not medical advice.

## Worked examples

1. transfer = 2026-09-01, embryo = 5 gives due = 2027-05-20, fertilization = 2026-08-27, dated = 2026-08-13. Source: ACOG Committee Opinion 700: for a day-5 embryo, the due date is 261 days from the embryo transfer date; hand calculation in content.mdx.
2. transfer = 2026-09-01, embryo = 3 gives due = 2027-05-22, fertilization = 2026-08-29. Source: ACOG Committee Opinion 700: for a day-3 embryo, the due date is 263 days from the embryo transfer date.
3. transfer = 2026-09-01, embryo = 6 gives due = 2027-05-19. Source: ACOG Committee Opinion 700 (due date from the embryo age and transfer date): 266 − 6 = 260 days, the same rule as the day-3 and day-5 examples.
4. transfer = 2026-09-01, embryo = 5, on = 2026-09-27 gives weeks = {"weeks":6,"days":3}, left = 235. Source: hand calculation in content.mdx: dated from August 13, 2026 (due date − 280 days); September 27 is 45 days later, 6 weeks 3 days; 235 days to May 20, 2027.

## FAQ

### How is an IVF due date calculated?

ACOG recommends dating an IVF pregnancy from the embryo's age and the transfer date. The due date is 266 days after fertilization, so it is the transfer date + 266 days − the embryo's age. For a day-5 embryo that is 261 days after transfer; for a day-3 embryo, 263 days.

### Is the due date different for a frozen embryo transfer?

No. The rule uses the embryo's age at transfer, not the calendar date of the egg retrieval. A day-5 embryo transferred on September 1 has the same due date whether it was fresh or frozen.

### Why am I "2 weeks pregnant" on the day of fertilization?

By convention, pregnancy is counted from the first day of the last period, about 2 weeks before ovulation and fertilization, and lasts 280 days. An IVF pregnancy is given the same dating, so the calculator counts weeks from the due date − 280 days.

### Is an IVF due date more accurate than one from a last period?

Yes. With IVF, the day of fertilization is known, so ACOG says the date from the embryo's age should be used to set the due date.

### Will my baby be born on the due date?

Probably not on that exact day. A due date is the day the pregnancy reaches 40 weeks. It is an estimate to plan care around, not a prediction of the birth day.

### What if my embryo was transferred on day 2 or day 4?

The same rule works for any embryo age: transfer date + 266 days − the embryo's age in days. The calculator offers days 3, 5, and 6, the most common ages at transfer.

## Sources

- American College of Obstetricians and Gynecologists. Committee Opinion No. 700: Methods for Estimating the Due Date. Obstetrics and Gynecology 2017;129:e150–e154. doi:10.1097/aog.0000000000002046