IVF due date calculator
Estimate an IVF or FET due date from your transfer day and embryo age (Day 3, Day 5, or Day 6). Planning math you can check against the portal — ultrasound still wins if they disagree. Estimate only — not medical advice.
Enter a transfer date to see an estimate.
What this page does
Clinics usually date an IVF pregnancy from the embryo's age on transfer day, not from a last menstrual period you never had. A Day 5 blastocyst does not get the same calendar add-on as a Day 3 embryo, and a frozen embryo transfer (FET) follows the thawed embryo's day age the same way — freezer months do not become pregnancy weeks.
Enter the transfer date and choose Day 3, Day 5, Day 6, or FET. This page returns an estimated due date (EDD) you can compare with the sticky note on your fridge, the discharge sheet in your bag, or the number sitting in your patient portal. The math is the familiar fertilization-length framework: roughly 266 days from fertilization, minus how old the embryo already was when it went in.
That is planning arithmetic, not a rewrite of your chart. If a dating ultrasound later moves the official EDD — crown-rump length, clinic policy, multiples — the scan and your doctor's notes win. Use this when you want Day 3 vs Day 5 spelled out in calendar days, or when a period app keeps asking for an LMP that does not exist in your story.
Nothing here is uploaded to a clinic EMR. The calculation is designed to run in your browser so you can sanity-check napkin math before beta, leave paperwork, or a group-chat debate about "plus two-sixty-something."
When to use
You just left transfer and someone said "plus two-sixty-something" too fast. You want Day 3 vs Day 5 side by side before you text the group chat. Your FET calendar and a random LMP app disagree by a week, and you need a calm second look at the arithmetic without a lecture about gestational-age theory.
It is also useful when you are filling a leave form, baby registry, travel plan, or work calendar and only have the transfer date written down. Partners who did not sit through the embryology explanation often need to see why +261 is not the same as "forty weeks from a fake period." Nurses sometimes quote an LMP-equivalent verbally; this page helps you see whether that number lines up with transfer-day math.
When not to
Do not use this to override a dating ultrasound your doctor already locked in. Once CRL dating is official, clinics usually follow the scan, not a browser widget — and arguing with a signed report using a sticky-note calculator is a bad use of everyone's time.
If you only have a due date and want to work backward into a conception window or LMP-equivalent, use the reverse due date calculator instead of inventing a transfer you do not have. Fresh egg retrieval without a transfer date is not enough input. Emergency symptoms, bleeding, or severe pain need clinical care, not another date tool.
Assumptions
We use the common fertilization-length framework: about 266 days from fertilization to due date, then subtract the embryo's age at transfer. That yields Day 3 → +263 days, Day 5 → +261, Day 6 → +260 from the transfer date.
FET uses the same day-age offset as a fresh transfer of the same age. Freeze or thaw duration does not add a second pregnancy clock by itself. We do not auto-apply clinic-specific "adjusted EDD" rules, twin protocols, vanishing-twin redating, assisted-hatching footnotes, or PGT calendar quirks. Leap days are handled as ordinary calendar addition — not a special "IVF leap rule."
Examples
Day 5 transfer · March 10, 2026 → EDD November 26, 2026. March 10 + 261 days under the 266 − 5 framework.
Day 3 transfer · June 1, 2026 → EDD February 19, 2027. June 1 + 263 days — two days later than a Day 5 transfer on the same date.
FET Day 5 · September 15, 2026 → EDD June 3, 2027. Same +261 as a fresh Day 5; freeze storage time does not add pregnancy days.
Gotchas
"Day 5" means embryo age from fertilization/retrieval culture, not the fifth day of the calendar month.
Some clinics quote dating as 280 days from an LMP-equivalent instead of saying +261 out loud — both should land near the same EDD if the LMP-equivalent was built correctly.
A later dating ultrasound can move the EDD; this tool does not read crown-rump length or upload scan measurements.
Twins, vanishing twin, early bleeding, or unusual protocols change clinical dating — not something a browser page can settle.
Retrieval day and transfer day are different inputs; using the wrong one slides the whole result by the culture interval.
Patient forums sometimes quote +266 from transfer for everyone; that ignores embryo age and will be late for Day 5.
Portal EDDs after the first OB ultrasound can differ from pure transfer math — that is expected, not a bug in your sticky note.
How this is calculated
The calculator is intentionally boring: one date you know, one embryo age, one calendar add-on. Showing the offset matters as much as the final EDD, because that is the piece people mis-copy from forums.
Nothing is uploaded. You pick the age label from your paperwork, enter the transfer day (not retrieval day unless they truly match), and read the estimate. If a hospital form still demands a last period, translate afterward with the IVF LMP-equivalent tool rather than inventing menses.
- Choose Day 3, Day 5, Day 6, or FET (FET commonly uses the Day 5 blastocyst offset unless your paperwork says otherwise).
- Enter the transfer date on your discharge sheet or patient portal — not retrieval day unless they are the same calendar day.
- Read the estimated due date and the day-age offset shown under it so you can explain the math later.
- If a hospital form demands an LMP, open the IVF LMP-equivalent calculator rather than inventing a period you did not have.
- Compare with the portal EDD; if they differ after a dating scan, the clinic's updated date usually wins.
- Confirm medical, travel, and leave decisions with your clinic — this page is a planning check, not a chart rewrite.
EDD ≈ transfer date + (266 − embryo age) Day 3 → +263 · Day 5 → +261 · Day 6 → +260
Related calculators
If you want the how-to phrasing people type after transfer — "calculate due date from IVF" — use that page; the engine matches. Frozen-only framing lives on the FET page so freezer myths stay out of the way.
Day 3 and Day 5 landings lock the age selector for people who searched those exact labels. Hospital paperwork that refuses to speak transfer language belongs on the IVF LMP-equivalent calculator. If your only reliable number is already an EDD, reverse dating is the better starting point than guessing a transfer.
See also: calculate due date from ivf, fet due date calculator, day 5 blastocyst transfer due date, and ivf lmp equivalent calculator.
FAQ
- How is an IVF due date calculated?
- Most clinics start from fertilization-length math: roughly 266 days from fertilization, adjusted for how old the embryo was at transfer. A Day 5 embryo has already lived five of those days in the lab, so you add about 261 days from transfer. Day 3 adds 263; Day 6 adds 260. The result is an estimated due date for planning — ultrasound policy can still update it later.
- Is an IVF due date the same as natural conception dating?
- Gestational age is still talked about in the same ~40-week framework, but you usually do not start from a real last menstrual period. The transfer date plus embryo age replaces the LMP guess. Apps that force an LMP field will invent nonsense if you feed them a period you never had.
- Does FET use a different formula?
- The day-age offset is the same idea. Freezing and thawing do not add extra pregnancy days by themselves. What matters is the embryo's age when it goes back in, counted from the FET date — not how long it sat in storage.
- Why does my period app show a different date?
- Many apps force an LMP field and assume a ~28-day cycle story. If you enter a real period from another chapter of your life, or invent one, they drift by a week or more. Use an IVF LMP-equivalent built from your EDD, or trust the clinic EDD on your portal.
- What if my clinic already gave me an EDD?
- Treat that as primary. This page is for checking sticky-note math and comparing Day 3 vs Day 5 offsets — not for arguing with a signed ultrasound report. If the portal and napkin math disagree after a scan, ask which rule the clinic is using.
- Should I date from retrieval or transfer?
- Transfer. Retrieval is when eggs were collected; culture days between retrieval and transfer are already reflected in the Day 3 / Day 5 / Day 6 label. Dating from retrieval without adjusting for those culture days is a common DIY mistake.
- Can twins or a vanishing twin change the date?
- Clinical dating for multiples and early losses can diverge from simple day-age math. This tool does not specialize in those protocols. Follow the dating policy your clinic explains after imaging.
- Is this medical advice?
- No. It is a planning estimate that runs in your browser. Confirm dating, testing, travel, and medical decisions with your clinic.