IVF Pregnancy Due Date Calculator (3-Day and 5-Day Embryo Transfer)
IVF removes the biggest source of error in pregnancy dating. With a natural conception the due date is estimated from the last menstrual period and assumes a textbook fourteen-day ovulation that many cycles do not follow. After an embryo transfer the developmental age of the embryo is known exactly, so the due date can be fixed to the day.
IVF due dates are more precise than LMP-based ones because the exact conception equivalent is known to the day.
| Milestone | Gestational age | Date |
|---|---|---|
| First beta hCG | 4w 0d | 10 May 2026 |
| Viability scan | 6w 3d | 27 May 2026 |
| End of first trimester | 13w 0d | 12 Jul 2026 |
| NT / combined screening | 12w 0d | 5 Jul 2026 |
| Anatomy scan | 20w 0d | 30 Aug 2026 |
| Viability threshold | 24w 0d | 27 Sept 2026 |
| Third trimester begins | 27w 0d | 18 Oct 2026 |
| Full term | 39w 0d | 10 Jan 2027 |
| Due date | 40w 0d | 17 Jan 2027 |
How the transfer date converts to gestational age
Gestational age is counted from the notional last menstrual period, two weeks before conception. A day-5 blastocyst transferred today is already nineteen days of gestational age — fourteen days of the notional pre-ovulatory phase plus five days of embryo development. Subtract the embryo age from the transfer date to get the conception equivalent, then add 266 days.
Day 3 versus day 5 transfers
A cleavage-stage day-3 embryo is transferred two days earlier in its development than a blastocyst, so its due date sits two days later from the same transfer date. Day-6 expanded blastocysts shift one day earlier again. Getting the stage right matters most for early scan scheduling, where a two-day error can change the interpretation of a viability scan.
Frozen transfers use the same maths
For a frozen embryo transfer, only the embryo's developmental stage at freezing and the transfer date matter — the time spent in cryostorage does not count toward gestational age at all. A blastocyst frozen for three years is still a day-5 embryo on the day it is transferred.
Due date offset by embryo stage
| Embryo stage | Days added to transfer date | Gestational age on transfer day | Notes |
|---|---|---|---|
| Day 2 (4-cell) | 266 − 2 = 264 | 2w 2d | Uncommon in modern protocols |
| Day 3 (cleavage) | 266 − 3 = 263 | 2w 3d | Standard cleavage transfer |
| Day 5 (blastocyst) | 266 − 5 = 261 | 2w 5d | Most common today |
| Day 6 (expanded) | 266 − 6 = 260 | 2w 6d | Frequent with FET cycles |
| Day 7 blastocyst | 266 − 7 = 259 | 3w 0d | Slower-developing embryos |
People also ask
How is an IVF due date calculated for a 5-day transfer?
Add 261 days to the transfer date — equivalent to subtracting the five days of embryo development from the transfer date and then adding the standard 266 days from conception to birth.
Why does my IVF due date differ from the LMP calculator?
LMP dating assumes a 28-day cycle with ovulation on day 14. IVF dating uses the known embryo age, which is exact, so the two can differ by several days in either direction.
Does time in the freezer affect the due date?
No. Cryopreservation pauses development entirely, so only the embryo's stage at freezing and the transfer date are used.
Three worked examples
Same engine, three different starting points — useful if you want to see how sensitive the answer is before you type your own numbers in.
Example 1: embryo stage at transfer "Day 3"
On the lower / more conservative end. IVF due dates are more precise than LMP-based ones because the exact conception equivalent is known to the day.
Example 2: embryo stage at transfer "Day 5"
A typical middle-of-the-road setup. IVF due dates are more precise than LMP-based ones because the exact conception equivalent is known to the day.
Example 3: embryo stage at transfer "Day 6"
On the higher / more demanding end. IVF due dates are more precise than LMP-based ones because the exact conception equivalent is known to the day.
Quick answers about the IVF Pregnancy Due Date
What exactly does the IVF Pregnancy Due Date work out?
IVF removes the biggest source of error in pregnancy dating. You enter embryo transfer date and embryo stage at transfer and the result panel updates straight away, so you can compare two or three versions of the same question in a few seconds.
What do I need before I start?
Only 2 fields: embryo transfer date and embryo stage at transfer. Nothing else is needed and nothing is stored.
How the transfer date converts to gestational age?
Gestational age is counted from the notional last menstrual period, two weeks before conception. The same maths runs inside this page, so hand-checking the result on paper gives you the identical figure.
Why do two calculators give me different answers for iVF Pregnancy Due Date?
A cleavage-stage day-3 embryo is transferred two days earlier in its development than a blastocyst, so its due date sits two days later from the same transfer date. Different sites pick different assumptions, so always check which method a calculator states before you trust the gap between two numbers.
What does the "Due date offset by embryo stage" table on this page tell me?
It is the reference range this tool works against — 5 rows from "Day 2 (4-cell)" (266 − 2 = 264) up to "Day 7 blastocyst" (266 − 7 = 259). Use it to sanity-check whether the number you just calculated sits where you expected it to.
Which embryo stage at transfer should I pick?
The dropdown offers 3 choices — Day 3, Day 5 and Day 6. Pick the one that matches your real situation rather than the one you would like to be true; embryo stage at transfer usually moves the final figure more than any other single input, so it is worth running it twice with the option above and below your guess.
Do I have to press a button or reload the page to see the result?
No. IVF Pregnancy Due Date runs completely inside your browser, so the moment you change a value the cards recalculate — there is no submit step, no page reload and no waiting for a server round trip. That also means it keeps working on a weak or intermittent mobile connection.
Is it free, and do you keep what I type?
It is free with no sign-up, no app install and no usage limit. Nothing you enter into IVF Pregnancy Due Date leaves your device — the calculation is JavaScript running locally, so there is no upload of your figures to DrHint or anyone else.
Can I use it on a phone?
Yes — the layout stacks to a single column on small screens and the number fields open the numeric keypad on both Android and iOS. Many people bookmark this page or add it to their home screen and re-open it whenever the question comes up.
Anything to be careful about with the result?
Add 261 days to the transfer date — equivalent to subtracting the five days of embryo development from the transfer date and then adding the standard 266 days from conception to birth. Treat the output as a well-grounded estimate for planning, not as a professional, legal or medical decision on its own.
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