What this IVF Due Date Calculator does
This English-language IVF due date calculator computes your estimated delivery date (EDD), equivalent last menstrual period (LMP), and current gestational age directly from your embryo transfer date — supporting day-3 cleavage embryos, day-5 blastocysts, and day-6 thawed blastocysts for both fresh and frozen embryo transfers (FET). Most generic due-date tools hard-code a day-5 fresh assumption, producing systematic two-day errors for the large share of cycles that use day-3 or day-6 day-6 thawed embryos. This calculator follows the ASRM/SART dating convention so that your gestational age maps correctly onto the standard prenatal milestones used in week-by-week pregnancy apps and clinical scheduling. 100% client-side — your data never leaves your browser. No uploads, no tracking, no server logs.
Features
- All three embryo stages. Correctly offsets the due date for day-3 cleavage, day-5 blastocyst, and day-6 thawed blastocyst transfers. A day-3 transfer is two days younger than a day-5, so the EDD shifts accordingly — an error that affects a meaningful portion of IVF cycles.
- Fresh and frozen (FET) support. Frozen embryo transfers are dated by the embryo's biological age, not the freeze date. This calculator treats fresh and FET cycles identically in terms of the dating math, which matches how ASRM and most IVF clinics assign gestational age.
- Equivalent LMP output. Returns the calculated LMP equivalent so you can enter it into any standard pregnancy tracking app or communicate it to an OB who uses LMP-based dating. The formula is: LMP = transfer date − 14 days − embryo age in days.
- Live gestational age. Displays your current gestational age in weeks and days as of today, recalculated each time you open the tool. Useful for confirming where you are relative to first-trimester screening windows like the NT scan at 11–14 weeks.
- Donor-egg and standard cycles. Donor-egg cycles use the embryo's age — not the recipient's cycle — which this calculator handles correctly. The egg donor's hormone timing has no bearing on the due date math once the transfer date and embryo stage are known.
- Private by design. All calculations run in your browser using JavaScript. No data is sent to any server, stored in a database, or linked to your identity. Sensitive reproductive health information stays on your device.
How to use the IVF Due Date Calculator
Three inputs, instant result. No account needed.
- Enter your transfer date. Select the calendar date on which the embryo was transferred to the uterus. Use the date your clinic documented — not the trigger shot date or egg retrieval date. Dates follow ISO 8601 format (YYYY-MM-DD) internally, which the Stack Overflow Developer Survey 2024 identifies as the most widely preferred date format among developers.
- Select the embryo stage. Choose day-3 cleavage embryo, day-5 blastocyst, or day-6 thawed blastocyst. If you are unsure, check your clinic's transfer summary or discharge paperwork — it is almost always documented there.
- Choose fresh or frozen (FET). Select Fresh if the embryo was transferred in the same cycle as egg retrieval, or Frozen (FET) if the embryo was cryopreserved first. The due date math is the same either way, but confirming this helps you verify you have selected the correct transfer date.
- Read your results. The calculator immediately displays your estimated due date, equivalent LMP, conception equivalent date, and current gestational age in weeks and days. Cross-check the EDD against your clinic letter — a difference of more than a day or two warrants a call to your coordinator.
Common use cases
- Confirming a clinic-provided due date. After your transfer, your clinic will give you an EDD. Use this calculator to verify it matches the standard ASRM formula. A one-day discrepancy is usually a rounding convention; a larger gap is worth clarifying before your first OB appointment.
- Syncing with a standard pregnancy app. Most pregnancy week-by-week apps ask for your LMP, not your transfer date. Enter the equivalent LMP this calculator returns and the app will correctly show your week-by-week milestones — anatomy scan at 18–22 weeks, viability at 24 weeks, and so on.
- Understanding day-3 versus day-5 transfer dating. Patients who had a day-3 transfer often notice their due date is two days earlier than friends who had day-5 blastocyst transfers on the same calendar date. This tool makes that offset explicit and helps you explain it to family members or a new OB unfamiliar with your cycle details.
- Planning a frozen embryo transfer cycle. If you are preparing for a FET and want to project a target due date before the cycle starts, enter a prospective transfer date and your intended embryo stage. This helps coordinate timing around work, travel, or scheduled breaks — especially useful for patients in cities like Chicago or Toronto who need to plan around unpredictable winter schedules.
- Education for first-time IVF patients. Many patients entering their first IVF cycle are surprised to learn that gestational age is counted from an equivalent LMP two weeks before egg retrieval, not from the transfer date itself. This calculator makes the math transparent and helps patients arrive at OB consultations with accurate dates. If you are also tracking nutrition during pregnancy, the [TDEE calculator](/en/tdee-calculator/) can help you estimate your caloric needs by trimester.
Frequently asked questions
Why is my IVF due date different from what a regular pregnancy calculator gives?
Standard pregnancy calculators assume ovulation on day 14 of a natural menstrual cycle and add 280 days from LMP. IVF dating works backward from the known transfer date and embryo age to calculate an equivalent LMP, then applies the same 280-day rule. Because IVF dating is anchored to a confirmed biological event rather than an estimated ovulation, ACOG Committee Opinion No. 700 recommends not redating an IVF pregnancy from first-trimester ultrasound unless the crown-rump length discrepancy exceeds 7 days — a stricter threshold than for spontaneous pregnancies.
Does it matter whether my transfer was fresh or frozen for the due date?
No — the due date formula is the same for fresh and frozen embryo transfers. What matters is the embryo's biological age (day 3, 5, or 6) and the calendar date of the transfer. In a frozen cycle the synthetic luteal phase controls uterine timing, but the embryo's developmental age is unchanged from when it was biopsied and frozen. Many online FET due date calculators correctly reflect this, but some older tools add or subtract extra days for frozen cycles — that is incorrect.
My clinic uses egg retrieval date instead of transfer date. Which is right?
Some clinics calculate the LMP equivalent as egg retrieval date + 14 days. For a day-5 fresh transfer, this is mathematically identical to transfer date − 5 days + 14 days = transfer date + 9 days, which matches the standard formula. For a day-3 transfer the offset differs by two days. Both approaches are defensible; what matters is consistency. If your clinic gave you a due date, enter their reference date into this calculator and verify the result matches. When in doubt, ask your coordinator which convention your clinic documents in the chart.
Does this calculator work for donor-egg IVF?
Yes. Donor-egg cycles use the embryo's age at transfer — exactly what this calculator uses. The egg donor's age, hormone levels, or retrieval date have no effect on the due date calculation for the recipient. Enter the transfer date and embryo stage as documented by your clinic.
Is my data private? Does the calculator send anything to a server?
All calculations happen entirely in your browser. No date, embryo stage, or result is transmitted to any server, stored in a database, or associated with your account or identity. You can verify this by opening your browser's network tab while using the tool — you will see no outbound requests triggered by the calculation. Sensitive reproductive health data stays on your device.
Can I use this calculator for twins or triplets from IVF?
Yes — the due date formula is the same regardless of how many embryos implanted. Multifetal pregnancies require different antepartum management and your OB or MFM specialist will adjust your care plan accordingly, but the mathematical relationship between transfer date, embryo stage, and EDD is unchanged. Note that twin and triplet pregnancies typically have earlier median delivery dates in practice, but the calculator reports the standard 280-day EDD by convention, consistent with how ASRM and SART report outcomes.