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IVF FET Due Date & Milestone Calculator

Zero-black-box IVF and Frozen Embryo Transfer (FET) due date calculator — see every step of the Day 3 / Day 5 / Day 6 / Day 7 formula, back-calculate your Virtual LMP, and compare singleton vs. DCDA/MCDA twin delivery windows.

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1. Cycle & embryo transfer details

Defaults pre-loaded (12 May 2026 · Day 5 Blastocyst · Singleton) so you can inspect the math immediately

Embryo stage / procedure type

Embryo transfer dateDay 0 of transfer

Clinic first β-hCG scheduleSets blood test milestone

Pregnancy type & twin chorionicity

Quick test presets (sets transfer relative to system clock):

Show the math

Step-by-step transparent derivation — always visible so you can verify every single day against your clinic chart

Transfer date = 12 May 2026
Embryo age at transfer = 5 days
Equivalent gestational age at transfer = 2w0d + 5d = 2w5d (19 days)
EDD = 12 May 2026 + 261 days = 28 Jan 2027 (40w0d = 280d − 19d remaining)
Virtual LMP = EDD − 280 days = 28 Jan 2027 − 280 days = 23 Apr 2026
Equivalent ovulation / fertilization = Virtual LMP + 14 days = 7 May 2026

Day 5 vs Day 6 changes the EDD by 0 days · Day 5 vs Day 3 changes it by 2 days

Why Day 5, Day 6, and Day 7 FET blastocysts all add +261 days: Regardless of whether your embryo reached the blastocyst stage on Day 5, Day 6, or Day 7 in the embryology lab, it is transferred into a uterus prepared with 5 days of progesterone exposure (2w5d gestational age). Therefore, ASRM and ACOG clinical guidelines assign 0 days difference between Day 5, Day 6, and Day 7 transfers (all use Transfer Date + 261 days). By contrast, a Day 3 embryo is 2 days younger at transfer (2w3d), shifting the EDD by +2 days (+263 days), and a Fresh Retrieval (Day 0) shifts it by +5 days (+266 days).

Protocol	Math Formula	GA at Transfer	Resulting EDD	Shift vs Day 5
Day 5 / Day 6 / Day 7 Blastocyst FET	`Transfer + 261 days`	2w5d (19 days)	28 Jan 2027	0 days (identical)
Day 3 Cleavage-Stage Embryo	`Transfer + 263 days`	2w3d (17 days)	30 Jan 2027	+2 days later
Fresh Egg Retrieval / Day 0 Fertilization	`Retrieval + 266 days`	2w0d (14 days)	2 Feb 2027	+5 days later

Reverse solver: “I know my EDD is X — what was my transfer date?”

Back-calculate your exact transfer date across all 4 protocols & audit 1–3 day clinic LMP discrepancies

Known Estimated Due Date (EDD)Enter the EDD given by your clinic

Clinic or OB app reported LMPCompare against exact Virtual LMP

Transfer Protocol	Back-Calculation Formula	Implied Transfer Date
Day 5 Blastocyst FET	`EDD − 261 days`	12 May 2026
Day 6 / Day 7 Blastocyst FET	`EDD − 261 days (0d shift)`	12 May 2026
Day 3 Cleavage Embryo	`EDD − 263 days`	10 May 2026
Fresh Egg Retrieval / Day 0	`EDD − 266 days`	7 May 2026

Exact Virtual LMP (EDD − 280d): 23 Apr 2026Clinic / App LMP: 25 Apr 2026Difference: +2 days

Why a 1–3 day difference between clinic LMP and Virtual LMP is normal: Many legacy EHR systems and paper OB wheels use Naegele's calendar rule (LMP + 9 calendar months + 7 days, which spans 281–283 days depending on 30/31-day months) or adjust LMP by 1–3 days after an early Crown-Rump Length (CRL) ultrasound scan. Per ACOG Committee Opinion #700, an IVF embryo transfer date is the most accurate dating anchor possible — a 1 to 3 day LMP or ultrasound variance is a harmless software/measurement artifact and is nothing to panic about.

Medical Disclaimer (Always Visible · Zero Clinic or Drug Affiliations)

This calculator is an educational reference built from published ASRM and ACOG obstetric dating equations (+261d for Day 5/6/7 blastocysts, +263d for Day 3 embryos, +266d for egg retrieval). It does not constitute medical advice, diagnosis, or prescription guidance. Always follow your Reproductive Endocrinologist (RE) and OB/GYN instructions for β-hCG testing, ultrasound scheduling, and progesterone/estrogen tapering. This page contains no fertility clinic lead generation and no pharmaceutical referral links.

How IVF & FET gestational dating works

Spontaneous pregnancy dating counts 280 days from the first day of the Last Menstrual Period (LMP), assuming ovulation occurred on Day 14. In an IVF or Frozen Embryo Transfer (FET) cycle, your actual calendar period is suppressed or unrelated to embryo transfer timing, so clinicians construct a Virtual (Corrected) LMP fixed at Transfer Date − (14 + Embryo Age).

Always give your Virtual LMP (23 Apr 2026) when registering at a general OB/GYN office or radiology center so their ultrasound software aligns to the exact day with your fertility clinic's transfer clock.

Live Gestational Ticker

Auto-synced with system clock (8 Nov 2026)

LIVE PREGNANCY TICKER

Today: 28w3d (dp5dt: 180)

Check another date:

Current Gestational Age

28w3d

3rd Trimester · 71.1% of 40w

Post-Transfer (dp5dt)

180 dp5dt

Equivalent to 185 dpo

Days to Next Milestone

53 days

MCDA Twin Delivery Window Opens (36w0d) (31 Dec 2026)

Official 40w0d EDD

28 Jan 2027

12 May 2026 + 261 days

Virtual LMP (for OB charts)

23 Apr 2026

Equiv. fertilization: 7 May 2026

Singleton vs. Twin Delivery Windows (Timeline)

Singleton 39w0d–40w6d · DCDA Twins 37w0d–37w6d · MCDA Twins 36w0d–36w6d

Horizontal Gestational & Delivery Window Timeline (2w to 41w)Your marker today: 28w3d (8 Nov 2026)

Gestation Type	Clinical Delivery Window	Calendar Date Range	Clinical Guidance
Singleton	`39w0d–40w6d`	21 Jan 2027 – 3 Feb 2027	Optimal ACOG full-term delivery window (includes ARRIVE 39w0d elective induction & 40w0d official EDD).
DCDA Twins (Dichorionic)	`37w0d–37w6d`	7 Jan 2027 – 13 Jan 2027	Two separate placentas and sacs — standard full-term clinical delivery target for uncomplicated twin IVF.
MCDA Twins (Monochorionic)	`36w0d–36w6d`	31 Dec 2026 – 6 Jan 2027	Shared placenta, two amniotic sacs — ACOG planned delivery window to reduce late cord/placental risks.

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6 Printable IVF Milestone Keepsake Cards & .ICS Calendar

Print photo-ready milestone cards or add all clinical dates to Apple, Google, or Outlook Calendar in one click

MILESTONE #14w0d · 9dp5dt

First Quantitative β-hCG Blood Test

21 May 2026

Clinic serum β-hCG check (typically ≥ 50–100 mIU/mL target at 14 dpo / 9dp5dt)

MILESTONE #26w4d · 27dp5dt

6w Viability & Fetal Heartbeat Ultrasound

8 Jun 2026

Fetal pole and cardiac activity measured (target 110–160 bpm at 6w3d–6w5d)

MILESTONE #310w0d · 51dp5dt

NIPT Cell-Free DNA & PIO / Estrogen Wean

2 Jul 2026

Placenta takes over hormone production; non-invasive prenatal testing window opens

MILESTONE #412w3d · 68dp5dt

NT Ultrasound & End of First Trimester

19 Jul 2026

Nuchal translucency scan (12w0d–13w6d); miscarriage risk drops below 1%

MILESTONE #58w4d · 41dp5dt

RE Fertility Clinic Graduation

22 Jun 2026

Transition from Reproductive Endocrinologist (RE) to regular OB/GYN care

MILESTONE #620w0d · 121dp5dt

20-Week Detailed Anatomy Scan

10 Sep 2026

Comprehensive mid-pregnancy fetal organ, heart, spine, and placental survey

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Milestone	Date	Gestational Age	IVF Notation	Status
Embryo Transfer Day Day 5 Blastocyst transferred into synchronized endometrium (2w5d)	12 May 2026	2w 5d	0dp5dt	Passed
Implantation Window Opens Zona hatching, apposition, and attachment to endometrium begin (6 dpo)	13 May 2026	2w 6d	1dp5dt	Passed
First Quantitative β-hCG Blood Test Clinic serum β-hCG check (typically ≥ 50–100 mIU/mL target at 14 dpo / 9dp5dt)	21 May 2026	4w 0d	9dp5dt	Passed
Repeat 48-Hour β-hCG Doubling Check Confirms normal 48–72 hour hCG doubling time (~60%+ two-day rise)	23 May 2026	4w 2d	11dp5dt	Passed
Placement Scan (Gestational & Yolk Sac) Transvaginal ultrasound confirms intrauterine gestational sac and yolk sac	1 Jun 2026	5w 4d	20dp5dt	Passed
6w Viability & Fetal Heartbeat Ultrasound Fetal pole and cardiac activity measured (target 110–160 bpm at 6w3d–6w5d)	8 Jun 2026	6w 4d	27dp5dt	Passed
RE Fertility Clinic Graduation Transition from Reproductive Endocrinologist (RE) to regular OB/GYN care	22 Jun 2026	8w 4d	41dp5dt	Passed
NIPT Cell-Free DNA & PIO / Estrogen Wean Placenta takes over hormone production; non-invasive prenatal testing window opens	2 Jul 2026	10w 0d	51dp5dt	Passed
NT Ultrasound & End of First Trimester Nuchal translucency scan (12w0d–13w6d); miscarriage risk drops below 1%	19 Jul 2026	12w 3d	68dp5dt	Passed
20-Week Detailed Anatomy Scan Comprehensive mid-pregnancy fetal organ, heart, spine, and placental survey	10 Sep 2026	20w 0d	121dp5dt	Passed
Viability Milestone & Glucose Screening Fetal viability landmark (24w0d) and gestational diabetes screening window	8 Oct 2026	24w 0d	149dp5dt	Passed
MCDA Twin Delivery Window Opens (36w0d) Clinical target window (36w0d–36w6d) for monochorionic diamniotic twins	31 Dec 2026	36w 0d	233dp5dt	In 53d
DCDA Twin Delivery Window Opens (37w0d) Clinical target window (37w0d–37w6d) for dichorionic diamniotic twins	7 Jan 2027	37w 0d	240dp5dt	In 60d
Official 40-Week Estimated Due Date (EDD) 266 days post-fertilization (261 days after Day 5 Blastocyst)	28 Jan 2027	40w 0d	261dp5dt	In 81d
Official 40-week singleton anchor	28 Jan 2027	40w 0d	261dp5dt	280d from Virtual LMP

Built from user complaints

What people hate about the other tools

We read the reviews of the incumbents before writing this page. Every complaint below maps to a decision in the tool above.

Patients transferring Day 6 or Day 7 frozen blastocysts are confused whether calculators count them like Day 5 (2w5d) or shift by a day.
r/IVF (Reddit) · Day 6/7 rule confusion
In this toolDisplays exact transfer math (+261/+263 days) with a clear toggle for Day 6/7 clinical Day-5 equivalent dating.
OB offices and pregnancy apps force a virtual LMP entry that is off by 1 to 3 days from the fertility clinic's exact transfer date.
r/IVF (Reddit) · 1-3 day LMP mismatch
In this toolAuto-computes your exact Corrected LMP and equivalent ovulation date so OB charts and apps match your clinic date.
Standard calculators only show a 40-week singleton due date, missing beta/ultrasound milestones and 36-37 week twin delivery windows.
r/InfertilityBabies (Reddit) · no IVF/twin milestones
In this toolMaps IVF milestones (beta dates, heartbeat scan, RE graduation) and highlights 36-37w DCDA/MCDA twin windows.

One-line difference: Transparent Day 3/5/6/7 FET & fresh transfer formula breakdown with corrected LMP, live XwYd + dpdt, and twin windows.

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Fresh, Day 3, Day 5 & Day 6/7 FET due date & corrected LMP calculator
Live gestational week+day (XwYd) and post-transfer (dpdt) dashboard
IVF milestone timeline & DCDA/MCDA twin full-term delivery windows

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High-res printable IVF milestone keepsake cards & PDF journal pages
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